foo.cc: In function 'int main(int, char**)':
foo.cc:12:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&x,&y);
  ~~~~~^~~~~~~~~~~~~~
foo.cc: In function 'void Input(int (*)[501], int, int, int, int)':
foo.cc:42:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d",&a[j][i]);
    ~~~~~^~~~~~~~~~~~~~~

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