To add nc50lc's reply:

You paid 169 sat as transaction fee for your first transaction and you replaced it with a transaction with the (virtual) size of ‎171 vB.
For the replacement transaction to be accepted by the nodes, you had to pay the minimum fee of 338 sat for that. Any transaction with lower fees would be rejected by nodes.

Here is where the 338 sat came from:

169 + 171 = 338 sat.

169 sat was the fee paid for the replaced transaction
171 sat was the fee required for the replacement transaction's own bandwidth.
 

For more information on RBF requirements, read BIP125 rules