2193

2193.cc

#include <iostream>
using namespace std;
long long d[91];
int main() {
    int n;
    cin >> n;
    d[1] = 1;
    d[2] = 1;
    for (int i=3; i<=n; i++) {
        d[i] = d[i-1] + d[i-2];
    }
    cout << d[n] << '\n';
    return 0;
}