foo.cc: In function 'int main()':
foo.cc:8:17: warning: unused variable 'a' [-Wunused-variable]
    8 |     int n,m,i,j,a;
      |                 ^
foo.cc:20:11: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized]
   20 |     cout<<j;
      |           ^

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