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