/in/foo.cc: In function 'int main()':
/in/foo.cc:5:11: warning: variable 'x' set but not used [-Wunused-but-set-variable]
   int n,m,x,y;
           ^
/in/foo.cc:5:13: warning: variable 'y' set but not used [-Wunused-but-set-variable]
   int n,m,x,y;
             ^