题解

#include <bits/stdc++.h>
using namespace std;
long long feibonaji[61];
long long f(long long n){
    if (n < 2)return 1;
    if (feibonaji[n] > 0)return feibonaji[n];
    feibonaji[n] = f(n-1)+f(n-2);
    return feibonaji[n];
}
int main(){
    int n;
    cin >> n;
    cout << f(n-1);
    return 0;
}