foo.cc: In function 'int main()':
foo.cc:28:16: error: 'f' was not declared in this scope
  printf("%d\n",f[n][0][0]+f[n][0][1]);
                ^
foo.cc:6:7: 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