Comparing two columns in Excel

Hello,

I have to compare the following 4 columns;

Code Amount Code Amount
100 213 101 25
101 465 102 35
102 149 103 56

Column 5 should show the list of all codes by comparing column 1 & 3 and column 6 should show the summed up amount of column 2 and 4 as shown below.

code amount
100 213
101 238
102 184
103 56

Please suggest a formula.