foo.cc: In function 'int main()':
foo.cc:7:18: error: 'm' was not declared in this scope
    7 |         if(sum+b<m){
      |                  ^
foo.cc:10:18: error: 'm' was not declared in this scope
   10 |         if(sum+b>m){
      |                  ^
foo.cc:13:12: error: 'sun' was not declared in this scope; did you mean 'sum'?
   13 |         if(sun+b==m){
      |            ^~~
      |            sum
foo.cc:13:19: error: 'm' was not declared in this scope
   13 |         if(sun+b==m){
      |                   ^

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