foo.cc: In function 'int main()':
foo.cc:35:14: warning: unused variable 'b' [-Wunused-variable]
   35 |    int n, a, b;
      |              ^
foo.cc:36:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   36 |    scanf("%d", &n);
      |    ~~~~~^~~~~~~~~~
foo.cc:37:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   37 |    scanf("%d", &a);
      |    ~~~~~^~~~~~~~~~

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