answer.code: In function ‘int main()’:
answer.code:12:17: error: return-statement with no value, in function returning ‘int’ [-fpermissive]
   12 |                 return ;
      |                 ^~~~~~
answer.code:9:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
    9 |         scanf("%lld",&n);
      |         ~~~~~^~~~~~~~~~~