题解

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