foo.cc: In function 'int main()':
foo.cc:6:12: warning: unused variable 'j' [-Wunused-variable]
  int n,s,i,j,a[1000000],x=0,b[1000000];
            ^
foo.cc:7:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&s);
  ~~~~~^~~~~~~~~~~~~~
foo.cc:9:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a[i]);
   ~~~~~^~~~~~~~~~~~

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