foo.cc: In function 'int main()':
foo.cc:13:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |  scanf("%d%d%lld%d",&m,&n,&k,&l);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:17:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   17 |    scanf("%lld",&s[i][j]);
      |    ~~~~~^~~~~~~~~~~~~~~~~

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