题解

#include <bits/stdc++.h>
using namespace std;
int main(){
int n;
scanf("%d",&n);
string A="4567",B="123",C="1234567";
while(C.size()<n)
{
A=B;
B=C;
C=B+A;
}
cout<<C[n-1]<<endl;
return 0;
}