Submission

Score: 100

User: yourmom

Problemset: อนุกรม

Language: cpp

Time: 0.005 second

Submitted On: 2026-10-03 10:50:17

#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;

    if (n <= 2) {
        cout << 1;
        return 0;
    }

    long long a = 1, b = 1, c;
    for (int i = 3; i <= n; i++) {
        c = a + b;
        a = b;
        b = c;
    }
    cout << b;
    return 0;
}