#include<iostream>
using namespace std;
int main() {
int n;
while (cin >> n) {
int* f = new int[n + 1];
f[0] = 1; f[1] = 1;
for (int i = 2; i <= n; i++) {
f[i] = f[i - 1] + f[i - 2];
}
cout << f[n] << endl;
delete[] f;
}
return 0;
}