#include <iostream>
#include <vector>
typedef long long ll;
using namespace std;
int main(){
    int N;
    ll M;
    cin>>N>>M;
    vector<ll> f(80,1);
    for(int i=2;i<80;i++){
        f[i]=f[i-1]+f[i-2];
    }
    int cnt=0;
    M=f[N-1]-M;
    for (int i=N-3;i>=0;i--){
        if (M>=f[i])M-=f[i],cnt++;
        if (M==0)break;
    }
    cout<<((M==0)?cnt:-1)<<endl;
    return 0;
}