#include <iostream>
#include <queue>
#include <cmath>
#include <vector>
using namespace std;

int rec(int x) {
    if(x <= 2) {
        return 1;
    }
    
    return rec(x - 1) + rec(x - 2);
}
int main()
{
    
    cout << rec(5) << endl;
  
    return 0;
}

// rec(5) = rec(4) +  rec(3)  = 3 + 2 = 5
// rec(4) = rec(3) + rec(2) = 2 + 1 = 3
// rec(3) = rec(2) + rec(1) = 1 + 1 = 2
// rec(2) = 1
// rec(1) = 1
// rec(2) = 2
// rec(3) = rec(2) + rec(1) = 1 + 1 = 2
// rec(2) = 1
// rec(1) = 1