/in/foo.cc: In function 'int main()':
/in/foo.cc:31:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k,l,n,m;
          ^
/in/foo.cc:31:12: warning: unused variable 'l' [-Wunused-variable]
  int i,j,k,l,n,m;
            ^
/in/foo.cc:31:16: warning: unused variable 'm' [-Wunused-variable]
  int i,j,k,l,n,m;
                ^