foo.cc: In function 'int main()':
foo.cc:21:22: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
         scanf("%d",&n);
                    ~~^
foo.cc:21:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&n);
         ~~~~~^~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务