foo.cc: In function 'int main()':
foo.cc:24:17: error: 'els' was not declared in this scope
   24 |                 els if(sum%2==1&&b==1)cout<<"y";
      |                 ^~~
foo.cc:25:17: error: 'else' without a previous 'if'
   25 |                 else cout<<"n";
      |                 ^~~~
foo.cc:11:23: warning: unused variable 'sum' [-Wunused-variable]
   11 |                 int t,sum=a+b;
      |                       ^~~

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