五十求调QAQ

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
#define int unsigned long long

signed main(){
    int a;
    cin>>a;
    int f[10000];
    f[0]=1;
    f[1]=1;
    if(a==1){
        cout<<1<<"\n";
    }
    else{
        for(int i=2;i<=a;i++){
            f[i]=f[i-1]+f[i-2];
        }
    }
    cout<<f[a];

}