ABC079B - Lucas Number

問題：B - Lucas Number

#include <iostream>
using namespace std;

#define FOR(i, a, b) for (int i = (a); i < (b); ++i)

int main(void) {
    int n;
    long long l[100];

    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> n;
    l[0] = 2;
    l[1] = 1;
    FOR(i, 2, n + 1) {
        l[i] = l[i - 2] + l[i - 1];
    }

    cout << l[n] << "\n";
    return 0;
}