foo.cc: In function 'int main()':
foo.cc:5:8: warning: unused variable 'm' [-Wunused-variable]
    5 |  int n,m,k,z;
      |        ^
foo.cc:5:10: warning: unused variable 'k' [-Wunused-variable]
    5 |  int n,m,k,z;
      |          ^
foo.cc:20:8: warning: 'z' may be used uninitialized in this function [-Wmaybe-uninitialized]
   20 |  cout<<z<<endl;
      |        ^

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