foo.cc:54:10: error: '::main' must return 'int'
 int main(){
          ^
foo.cc: In function 'int main()':
foo.cc:58:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld%lld%lld",&x,&y,&z);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:63:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld",&x);
   ~~~~~^~~~~~~~~~~

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