为什么这个代码会RE

#include<iostream>
#include<cctype>
#include<cstring>
using namespace std;
string s;
int main(){
	int i=0;
	while((s[i]=getchar())!='\n')i++;
//	cout<<s[s.size()-1]<<"\n";
	if(s.size()>=114500){
		cout<<"ikun";
	}else if(s[s.size()-2]=='m'){
		cout<<"ngm";
	}else if(s[0]=='j'){
		cout<<"ikun";
	}else{
		cout<<"jntm";
	}
	return 0;
}