/in/foo.cc: In function 'int main()':
/in/foo.cc:6:9: error: expected initializer before 'long'
    6 |         long long sum=0;
      |         ^~~~
/in/foo.cc:7:17: error: 'n' was not declared in this scope
    7 |         cin>>m>>n;
      |                 ^
/in/foo.cc:11:17: error: 'sum' was not declared in this scope
   11 |                 sum+=i;
      |                 ^~~
/in/foo.cc:13:15: error: 'sum' was not declared in this scope
   13 |         cout<<sum;
      |               ^~~