Submission

Status:

PPPPPPPPPP

Subtask/Task Score:

100/100

Score: 100

User: MrPian

Problemset: อนุกรม

Language: cpp

Time: 0.002 second

Submitted On: 2025-10-13 11:25:24

#include<iostream>
using namespace std;
int main(){
    int a;
    cin >> a;
    if(a <= 2){
        cout << 1;
        return 0;
    }
    unsigned long long s1 = 1, s2 = 1, s3 = 0;
    for(int i = 3; i <= a; ++i){
        s3 = s1 + s2;
        s1 = s2;
        s2 = s3;
    }
    cout << s3;
    return 0;
}