Transaction

[Error Code: 1101] cadence runtime error Execution failed:
error: underflow
  --> 0cb6dc8bc5fb9cb575c07e693ce55bfa51c76ee8decd38214a18d0dbe8c70f64:16:8
   |
16 |         let total: UFix64 = SwapConfig.ScaledUInt256ToUFix64(res) - 0.2
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^