Since there's a 4 letters limit for each number


Enter 1e19 so that it gets overflow to `9223372036854775807 (2 ^ 63 - 1)`

Add 1 and it becomes `2 ^ 63` thus flipping the sign bit and we get a negative number `-9223372036854775808`

Submit `[1e19, 1]` and win a flag:


Flag: `ENO{INTVAL_IS_NOT_ALW4S_P0S1TiV3!}`