#include<bits/stdc++.h>
#define REP(x,y,z) for(int x=y;x<=z;x++)
#define FORD(x,y,z) for(int x=y;x>=z;x--)
#define MSET(x,y) memset(x,y,sizeof(x))
#define FOR(x,y) for(__typeof(y.begin()) x=y.begin();x!=y.end();x++)
#define F first
#define S second
#define MP make_pair
#define PB push_back
#define SZ size()
#define M 85
void RI(){}
template<typename... T>
void RI( int& head, T&... tail ) {
    scanf("%d",&head);
    RI(tail...);
}
using namespace std;
typedef long long LL;
int n;
LL m;
LL fib[M];
int main()
{
	fib[1]=fib[2]=1;
	REP(i,3,M-1) fib[i]=fib[i-1]+fib[i-2];
	
	
	while(~scanf("%d %lld",&n,&m))
	{
		m = fib[n]-m;
		int ans=0;
		FORD(i,n-2,1) if(m>=fib[i])
		{
			m -= fib[i];
			ans++;
		}

		if(!m) printf("%d\n",ans);
		else puts("-1");
	}
	return 0;
}