foo.cc: In function 'int main()':
foo.cc:10:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 |     scanf("%d%lld",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~~~
foo.cc:11:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |     for(i=1;i<=n;i++) scanf("%d",&a[0][i]),a[0][i]--;
      |                       ~~~~~^~~~~~~~~~~~~~~

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