c++超简单题解

#include<iostream>
#include<string>
using namespace std;
int main(){
    string a="4567",b="123",c;
    int n;
    cin>>n;
    while(c.size()<n){
        c=b+a;
        a=b,b=c;
    }
    cout<<c[n-1];
    return 0;
}