/in/foo.cc: In function 'int main()':
/in/foo.cc:34:5: error: 'fin' was not declared in this scope
   34 |     fin >> m >> n;
      |     ^~~
/in/foo.cc:77:13: error: 'fout' was not declared in this scope
   77 |             fout << canvas[i][j];
      |             ^~~~
/in/foo.cc:79:9: error: 'fout' was not declared in this scope
   79 |         fout << endl;
      |         ^~~~