foo.cc: In function 'int main()':
foo.cc:36:16: warning: unused variable 'k' [-Wunused-variable]
  int x,y,z,i,j,k,m;
                ^
foo.cc:37:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~
foo.cc:42:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d",&x,&y,&z);
   ~~~~~^~~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务