/in/foo.cc: In function 'int main()':
/in/foo.cc:18:20: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'int' [-Wformat=]
  scanf("%d%d\n",n,m);
                    ^
/in/foo.cc:18:20: warning: format '%d' expects argument of type 'int*', but argument 3 has type 'int' [-Wformat=]
/in/foo.cc:19:13: error: 's' was not declared in this scope
  scanf("%c",s);
             ^