/in/foo.cc: In function 'int main()':
/in/foo.cc:21:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0;j <=s[i].length();j++)
                 ~~^~~~~~~~~~~~~~~
/in/foo.cc:20:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int i = 1;i <= n;i++)
  ^~~
/in/foo.cc:25:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   cout<<sum;
   ^~~~