foo.cc:13:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   13 | main(){
      |      ^
foo.cc: In function 'int main()':
foo.cc:14:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   14 |     scanf("%lld",&n);
      |     ~~~~~^~~~~~~~~~~
foo.cc:16:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   16 |         scanf("%lld %lld",m+i,a+i);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~

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