Transaction

[Error Code: 1101] error caused by: 1 error occurred:
	* transaction invocation failed when executing transaction: [Error Code: 1101] cadence runtime error: Execution failed:
error: underflow
  --> 1496fdc679610528b4c79add61734ebc312557734f62bd40c7aca7ed387b491a:16:8
   |
16 |         let total: UFix64 = SwapConfig.ScaledUInt256ToUFix64(res) - 0.2
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^