Transaction

[Error Code: 1101] cadence runtime error Execution failed:
error: underflow
  --> 4fc6d91de9abc02e86f2b9d182a0204dd5ebe2e0908dad553c0bcb4b9eb0dd51:16:8
   |
16 |         let total: UFix64 = SwapConfig.ScaledUInt256ToUFix64(res) - 0.2
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^