/in/foo.cc: In function 'int main()':
/in/foo.cc:6:8: warning: unused variable 'm' [-Wunused-variable]
    6 |  int n,m,k;
      |        ^
/in/foo.cc:6:10: warning: unused variable 'k' [-Wunused-variable]
    6 |  int n,m,k;
      |          ^