#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cctype>
#include<cstdlib>
#include<algorithm>
#include<bitset>
#include<vector>
#include<list>
#include<deque>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<sstream>
#include<fstream>
#include<iomanip>
#include<ctime>
#include<complex>
#include<functional>
#include<climits>
#include<cassert>
#include<iterator>
#include<unordered_set>
#include<unordered_map>
#include<bitset>
using namespace std;
int n;
long long int m;
map<pair<long long int, long long int>, int> mp[82];
inline int dfs(int c,long long int a, long long int b){
	if (clock() / (double)(CLOCKS_PER_SEC) > 1.8){
		return -1;
	}
	if (b > m){
		return -1;
	}
	if (c == n){
		if (b == m){
			return 0;
		}
		return -1;
	}
	if (mp[c].count(make_pair(a, b))){
		return mp[c][make_pair(a, b)];
	}
	int ans=dfs(c + 1, b, a + b);
	int ans2 = dfs(c + 1, b, a + b - 1LL);
	if (ans2 != -1){
		if (ans == -1 || ans > ans2){
			ans = ans2+1;
		}
	}
	mp[c][make_pair(a, b)] = ans;
	return mp[c][make_pair(a, b)];
}
int main(){
	scanf("%d", &n);
	scanf("%lld", &m);
	int ans=dfs(2, 1, 1);
	printf("%d\n", ans);
	return 0;
}