foo.cc: In function 'int main()':
foo.cc:24:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s",a);
  ~~~~~^~~~~~~~
foo.cc:25:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s",b);
  ~~~~~^~~~~~~~

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