foo.cc: In function 'int main()':
foo.cc:9:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |     scanf ("%d",&n);
      |     ~~~~~~^~~~~~~~~
foo.cc:11:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |         scanf ("%d%d",a+i,b+i);
      |         ~~~~~~^~~~~~~~~~~~~~~~

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