我的英语作业咋没那么简单呢

ez

#include<bits/stdc++.h> 
#define int long long
using namespace std;
signed main()
{
	string s;
	cin>>s;
	int n=s.size();
	if(n>=3)
	{
		if(s[n-1]=='r'&&s[n-2]=='e')
		{
			cout<<"er";
		}
		else
		{
			cout<<"ist";
		}
	}
	else
	{
		cout<<"er";
	}
}