foo.cc:2:19: warning: extra tokens at end of #include directive
    2 | #include<iostream>
#include<cmath>
      |                   ^
foo.cc: In function 'int main()':
foo.cc:8:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    8 |     scanf("%d",&w);
      |     ~~~~~^~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务