foo.cc: In function 'void init()':
foo.cc:25:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   25 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
foo.cc:29:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   29 |             scanf("%d",&a);
      |             ~~~~~^~~~~~~~~

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