#include #define GET_MACRO(a, b, c, NAME, ...) NAME #define rep(...) GET_MACRO(__VA_ARGS__, rep3, rep2)(__VA_ARGS__) #define rep2(i, a) rep3 (i, 0, a) #define rep3(i, a, b) for (int i = (a); i < (b); i++) #define repr(...) GET_MACRO(__VA_ARGS__, repr3, repr2)(__VA_ARGS__) #define repr2(i, a) repr3 (i, 0, a) #define repr3(i, a, b) for (int i = (b) - 1; i >= (a); i--) template inline bool chmin(T1 &a, T2 b) { return b < a && (a = b, true); } template inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); } using namespace std; typedef long long ll; ll F[100]; int main() { F[0] = 1; F[1] = 1; rep (i, 2, 100) F[i] = F[i - 1] + F[i - 2]; ll N, M; cin >> N >> M; ll diff = F[N - 1] - M; int ans = 0; repr (i, N + 1) { if (diff - F[i] >= 0) { diff -= F[i]; ans++; } } if (diff != 0) { cout << -1 << endl; } else { cout << ans << endl; } return 0; }