diff --git a/test/til/lang.go b/test/til/lang.go
index b96ccc0..7802568 100644
--- a/test/til/lang.go
+++ b/test/til/lang.go
@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"math/big"
 	"sort"
 	"strconv"
 
@@ -61,8 +62,8 @@ type instruction struct {
 	literal    string
 	from       string
 	to         string
-	amount     uint64
-	loadAmount uint64
+	amount     *big.Int
+	loadAmount *big.Int
 	fee        uint8
 	tokenID    common.TokenID
 	typ        common.TxType // D: Deposit, T: Transfer, E: ForceExit
@@ -433,30 +434,30 @@ func (p *parser) parseLine(setType setType) (*instruction, error) {
 		// deposit case
 		_, lit = p.scanIgnoreWhitespace()
 		c.literal += lit
-		loadAmount, err := strconv.Atoi(lit)
-		if err != nil {
+		loadAmount, ok := new(big.Int).SetString(lit, 10)
+		if !ok {
 			line, _ := p.s.r.ReadString('\n')
 			c.literal += line
-			return c, err
+			return c, fmt.Errorf("Can not parse number for LoadAmount")
 		}
-		c.loadAmount = uint64(loadAmount)
+		c.loadAmount = loadAmount
 		if err := p.expectChar(c, ","); err != nil {
 			return c, err
 		}
 	}
 	_, lit = p.scanIgnoreWhitespace()
 	c.literal += lit
-	amount, err := strconv.Atoi(lit)
-	if err != nil {
+	amount, ok := new(big.Int).SetString(lit, 10)
+	if !ok {
 		line, _ := p.s.r.ReadString('\n')
 		c.literal += line
-		return c, err
+		return c, fmt.Errorf("Can not parse number for Amount: %s", lit)
 	}
 	if c.typ == common.TxTypeDeposit ||
 		c.typ == common.TxTypeCreateAccountDeposit {
-		c.loadAmount = uint64(amount)
+		c.loadAmount = amount
 	} else {
-		c.amount = uint64(amount)
+		c.amount = amount
 	}
 	if fee {
 		if err := p.expectChar(c, "("); err != nil {
diff --git a/test/til/lang_test.go b/test/til/lang_test.go
index 893e4f0..a4346d1 100644
--- a/test/til/lang_test.go
+++ b/test/til/lang_test.go
@@ -117,7 +117,7 @@ func TestParseErrors(t *testing.T) {
 	`
 	parser := newParser(strings.NewReader(s))
 	_, err := parser.parse()
-	assert.Equal(t, "Line 2: Deposit(1)A:: 10\n, err: strconv.Atoi: parsing \":\": invalid syntax", err.Error())
+	assert.Equal(t, "Line 2: Deposit(1)A:: 10\n, err: Can not parse number for Amount: :", err.Error())
 
 	s = `
 		Type: Blockchain
diff --git a/test/til/txs.go b/test/til/txs.go
index 48d1afa..b9a090c 100644
--- a/test/til/txs.go
+++ b/test/til/txs.go
@@ -195,11 +195,11 @@ func (tc *Context) GenerateBlocks(set string) ([]common.BlockData, error) {
 				FromBJJ:     tc.Users[inst.from].BJJ.Public(),
 				TokenID:     inst.tokenID,
 				Amount:      big.NewInt(0),
-				LoadAmount:  big.NewInt(int64(inst.loadAmount)),
+				LoadAmount:  inst.loadAmount,
 				Type:        inst.typ,
 			}
 			if inst.typ == common.TxTypeCreateAccountDepositTransfer {
-				tx.Amount = big.NewInt(int64(inst.amount))
+				tx.Amount = inst.amount
 			}
 			testTx := L1Tx{
 				lineNum:     inst.lineNum,
@@ -222,11 +222,11 @@ func (tc *Context) GenerateBlocks(set string) ([]common.BlockData, error) {
 			tx := common.L1Tx{
 				TokenID:    inst.tokenID,
 				Amount:     big.NewInt(0),
-				LoadAmount: big.NewInt(int64(inst.loadAmount)),
+				LoadAmount: inst.loadAmount,
 				Type:       inst.typ,
 			}
 			if inst.typ == common.TxTypeDepositTransfer {
-				tx.Amount = big.NewInt(int64(inst.amount))
+				tx.Amount = inst.amount
 			}
 			testTx := L1Tx{
 				lineNum:     inst.lineNum,
@@ -243,7 +243,7 @@ func (tc *Context) GenerateBlocks(set string) ([]common.BlockData, error) {
 				return nil, fmt.Errorf("Line %d: %s", inst.lineNum, err.Error())
 			}
 			tx := common.L2Tx{
-				Amount:      big.NewInt(int64(inst.amount)),
+				Amount:      inst.amount,
 				Fee:         common.FeeSelector(inst.fee),
 				Type:        common.TxTypeTransfer,
 				EthBlockNum: tc.blockNum,
@@ -264,7 +264,7 @@ func (tc *Context) GenerateBlocks(set string) ([]common.BlockData, error) {
 			}
 			tx := common.L1Tx{
 				TokenID:    inst.tokenID,
-				Amount:     big.NewInt(int64(inst.amount)),
+				Amount:     inst.amount,
 				LoadAmount: big.NewInt(0),
 				Type:       common.TxTypeForceTransfer,
 			}
@@ -285,7 +285,7 @@ func (tc *Context) GenerateBlocks(set string) ([]common.BlockData, error) {
 			tx := common.L2Tx{
 				ToIdx:       common.Idx(1), // as is an Exit
 				Fee:         common.FeeSelector(inst.fee),
-				Amount:      big.NewInt(int64(inst.amount)),
+				Amount:      inst.amount,
 				Type:        common.TxTypeExit,
 				EthBlockNum: tc.blockNum,
 			}
@@ -306,7 +306,7 @@ func (tc *Context) GenerateBlocks(set string) ([]common.BlockData, error) {
 			tx := common.L1Tx{
 				ToIdx:      common.Idx(1), // as is an Exit
 				TokenID:    inst.tokenID,
-				Amount:     big.NewInt(int64(inst.amount)),
+				Amount:     inst.amount,
 				LoadAmount: big.NewInt(0),
 				Type:       common.TxTypeForceExit,
 			}
@@ -547,7 +547,7 @@ func (tc *Context) GeneratePoolL2Txs(set string) ([]common.PoolL2Tx, error) {
 			tx := common.PoolL2Tx{
 				FromIdx:     tc.Users[inst.from].Accounts[inst.tokenID].Idx,
 				TokenID:     inst.tokenID,
-				Amount:      big.NewInt(int64(inst.amount)),
+				Amount:      inst.amount,
 				Fee:         common.FeeSelector(inst.fee),
 				Nonce:       tc.Users[inst.from].Accounts[inst.tokenID].Nonce,
 				State:       common.PoolL2TxStatePending,
@@ -589,7 +589,7 @@ func (tc *Context) GeneratePoolL2Txs(set string) ([]common.PoolL2Tx, error) {
 				ToIdx:   common.Idx(1), // as is an Exit
 				Fee:     common.FeeSelector(inst.fee),
 				TokenID: inst.tokenID,
-				Amount:  big.NewInt(int64(inst.amount)),
+				Amount:  inst.amount,
 				Nonce:   tc.Users[inst.from].Accounts[inst.tokenID].Nonce,
 				State:   common.PoolL2TxStatePending,
 				Type:    common.TxTypeExit,