#define _CRT_SECURE_NO_WARNINGS #define _USE_MATH_DEFINES #pragma comment (linker, "/STACK:526000000") #include "bits/stdc++.h" using namespace std; typedef string::const_iterator State; #define eps 1e-8L #define MAX_MOD 1000000007LL #define GYAKU 500000004LL #define MOD 998244353LL #define pb push_back #define mp make_pair typedef long long ll; typedef float ld; #define REP(a,b) for(long long (a) = 0;(a) < (b);++(a)) #define ALL(x) (x).begin(),(x).end() int is_ok(int now) { int cnts[10] = {}; while (now != 0) { cnts[now % 10]++; if (cnts[now % 10] == 2) return false; now /= 10; } return true; } int is_Prime(int now) { if (now == 1) return false; for (int i = 2; i * i <= now; ++i) { if (now % i == 0) return false; } return true; } class EllysDifferentPrimes { public:static int getClosest(int n) { REP(q, 1e9) { if (n - q > 0 and is_ok(n - q) == 1 and is_Prime(n - q) == 1) { return n - q; } if (is_ok(n + q) == 1 and is_Prime(n + q) == 1) { return n + q; } } return -1; } }; // geometry library typedef complex Point; typedef pair, complex> Line; typedef struct Circle { complex center; long double r; }Circle; long double dot(Point a, Point b) { return (a.real() * b.real() + a.imag() * b.imag()); } long double cross(Point a, Point b) { return (a.real() * b.imag() - a.imag() * b.real()); } long double Dist_Line_Point(Line a, Point b) { if (dot(a.second - a.first, b - a.first) < eps) return abs(b - a.first); if (dot(a.first - a.second, b - a.second) < eps) return abs(b - a.second); return abs(cross(a.second - a.first, b - a.first)) / abs(a.second - a.first); } int is_intersected_ls(Line a, Line b) { return (cross(a.second - a.first, b.first - a.first) * cross(a.second - a.first, b.second - a.first) < eps) && (cross(b.second - b.first, a.first - b.first) * cross(b.second - b.first, a.second - b.first) < eps); } Point intersection_l(Line a, Line b) { Point da = a.second - a.first; Point db = b.second - b.first; return a.first + da * cross(db, b.first - a.first) / cross(db, da); } long double Dist_Line_Line(Line a, Line b) { if (is_intersected_ls(a, b) == 1) { return 0; } return min({ Dist_Line_Point(a,b.first), Dist_Line_Point(a,b.second),Dist_Line_Point(b,a.first),Dist_Line_Point(b,a.second) }); } pair intersection_Circle_Circle(Circle a, Circle b) { long double dist = abs(a.center - b.center); assert(dist <= eps + a.r + b.r); assert(dist + eps >= abs(a.r - b.r)); Point target = b.center - a.center; long double pointer = target.real() * target.real() + target.imag() * target.imag(); long double aa = pointer + a.r * a.r - b.r * b.r; aa /= 2.0L; Point l{ (aa * target.real() + target.imag() * sqrt(pointer * a.r * a.r - aa * aa)) / pointer, (aa * target.imag() - target.real() * sqrt(pointer * a.r * a.r - aa * aa)) / pointer }; Point r{ (aa * target.real() - target.imag() * sqrt(pointer * a.r * a.r - aa * aa)) / pointer, (aa * target.imag() + target.real() * sqrt(pointer * a.r * a.r - aa * aa)) / pointer }; r = r + a.center; l = l + a.center; return mp(l, r); } //end of geometry ll gcd(ll a, ll b) { if (b == 0) return a; return gcd(b, a % b); } template A pows(A val, ll b) { assert(b >= 1); A ans = val; b--; while (b) { if (b % 2) { ans *= val; } val *= val; b /= 2LL; } return ans; } template class Compressor { public: bool is_zipped = false; map zipper; map unzipper; queue fetcher; Compressor() { is_zipped = false; zipper.clear(); unzipper.clear(); } void add(A now) { assert(is_zipped == false); zipper[now] = 1; fetcher.push(now); } void exec() { assert(is_zipped == false); int cnt = 0; for (auto i = zipper.begin(); i != zipper.end(); ++i) { i->second = cnt; unzipper[cnt] = i->first; cnt++; } is_zipped = true; } ll fetch() { assert(is_zipped == true); A hoge = fetcher.front(); fetcher.pop(); return zipper[hoge]; } ll zip(A now) { assert(is_zipped == true); assert(zipper.find(now) != zipper.end()); return zipper[now]; } A unzip(ll a) { assert(is_zipped == true); assert(a < unzipper.size()); return unzipper[a]; } ll next(A now) { auto x = zipper.upper_bound(now); if (x == zipper.end()) return zipper.size(); return (ll)((*x).second); } ll back(A now) { auto x = zipper.lower_bound(now); if (x == zipper.begin()) return -1; x--; return (ll)((*x).second); } }; template class Matrix { public: vector> data; Matrix(vector> a) :data(a) { } Matrix operator + (const Matrix obj) { vector> ans; assert(obj.data.size() == this->data.size()); assert(obj.data[0].size() == this->data[0].size()); REP(i, obj.data.size()) { ans.push_back(vector()); REP(q, obj.data[i].size()) { A hoge = obj.data[i][q] + (this->data[i][q]); ans.back().push_back(hoge); } } return Matrix(ans); } Matrix operator - (const Matrix obj) { vector> ans; assert(obj.data.size() == this->data.size()); assert(obj.data[0].size() == this->data[0].size()); REP(i, obj.data.size()) { ans.push_back(vector()); REP(q, obj.data[i].size()) { A hoge = this->data[i][q] - obj.data[i][q]; ans.back().push_back(hoge); } } return Matrix(ans); } Matrix operator * (const Matrix obj) { vector> ans; assert(obj.data.size() == this->data[0].size()); REP(i, this -> data.size()) { ans.push_back(vector()); REP(q, obj.data[0].size()) { A hoge = ((this->data[i][0]) * (obj.data[0][q])); for (int t = 1; t < obj.data.size(); ++t) { hoge += ((this->data[i][t]) * obj.data[t][q]); } ans.back().push_back(hoge); } } return Matrix(ans); } Matrix& operator *= (const Matrix obj) { *this = (*this * obj); return *this; } Matrix& operator += (const Matrix obj) { *this = (*this + obj); return *this; } Matrix& operator -= (const Matrix obj) { *this = (*this - obj); return *this; } }; struct Fraction { ll a; ll b; Fraction() :a(0LL), b(1LL) { } Fraction(ll c, ll d) { int hoge = gcd(llabs(c), llabs(d)); c /= hoge; d /= hoge; if (d < 0) { d *= -1; c *= -1; } a = c; b = d; } bool operator <(Fraction rhs) const { return a * rhs.b < rhs.a * b; } }; template class modint { public: using u64 = std::uint_fast64_t; u64 value = 0; modint() :value(0LL) { } modint(ll a) : value(((a% mod) + 2 * mod) % mod) { } constexpr modint operator+(const modint rhs) const { return modint(*this) += rhs; } constexpr modint operator-(const modint rhs) const { return modint(*this) -= rhs; } constexpr modint operator*(const modint rhs) const { return modint(*this) *= rhs; } constexpr modint operator/(const modint rhs) const { return modint(*this) /= rhs; } constexpr modint& operator+=(const modint rhs) { value += rhs.value; if (value >= mod) { value -= mod; } return *this; } constexpr modint& operator-=(const modint rhs) { if (value < rhs.value) { value += mod; } value -= rhs.value; return *this; } constexpr modint& operator*=(const modint rhs) { value = (value * rhs.value) % mod; return *this; } constexpr modint& operator/=(modint rhs) { ll rem = mod - 2; while (rem) { if (rem % 2) { *this *= rhs; } rhs *= rhs; rem /= 2LL; } return *this; } bool operator <(modint rhs) const { return value < rhs.value; } friend ostream& operator<<(ostream& os, modint& p) { os << p.value; return (os); } }; class Dice { public: vector vertexs; //Up: 0,Left: 1,Center: 2,Right: 3,Adj: 4, Down: 5 Dice(vector init) :vertexs(init) { } //Look from Center void RtoL() { for (int q = 1; q < 4; ++q) { swap(vertexs[q], vertexs[q + 1]); } } void LtoR() { for (int q = 3; q >= 1; --q) { swap(vertexs[q], vertexs[q + 1]); } } void UtoD() { swap(vertexs[5], vertexs[4]); swap(vertexs[2], vertexs[5]); swap(vertexs[0], vertexs[2]); } void DtoU() { swap(vertexs[0], vertexs[2]); swap(vertexs[2], vertexs[5]); swap(vertexs[5], vertexs[4]); } bool ReachAble(Dice now) { set hoge; queue next; next.push(now); hoge.insert(now); while (next.empty() == false) { Dice seeing = next.front(); next.pop(); if (seeing == *this) return true; seeing.RtoL(); if (hoge.count(seeing) == 0) { hoge.insert(seeing); next.push(seeing); } seeing.LtoR(); seeing.LtoR(); if (hoge.count(seeing) == 0) { hoge.insert(seeing); next.push(seeing); } seeing.RtoL(); seeing.UtoD(); if (hoge.count(seeing) == 0) { hoge.insert(seeing); next.push(seeing); } seeing.DtoU(); seeing.DtoU(); if (hoge.count(seeing) == 0) { hoge.insert(seeing); next.push(seeing); } } return false; } bool operator ==(const Dice& a) { for (int q = 0; q < 6; ++q) { if (a.vertexs[q] != (*this).vertexs[q]) { return false; } } return true; } bool operator <(const Dice& a) const { return (*this).vertexs < a.vertexs; } }; pair TwoDimDice(int center, int up) { int target = 1; while (true) { if (center != target && 7 - center != target && up != target && 7 - up != target) { break; } target++; } return mp(Dice(vector{up, target, center, 7 - target, 7 - center, 7 - up}), Dice(vector{up, 7 - target, center, target, 7 - center, 7 - up})); } tuple OneDimDice(int center) { int bo = min(center, 7 - center); pair goa; if (bo == 1) { goa = mp(2, 3); } else if (bo == 2) { goa = mp(1, 3); } else if (bo == 3) { goa = mp(1, 2); } tuple now = make_tuple(Dice(vector{goa.first, goa.second, center, 7 - goa.second, 7 - center, 7 - goa.first}), Dice(vector{goa.first, 7 - goa.second, center, goa.second, 7 - center, 7 - goa.first}), Dice(vector{7 - goa.first, goa.second, center, 7 - goa.second, 7 - center, goa.first}), Dice(vector{7 - goa.first, 7 - goa.second, center, goa.second, 7 - center, goa.first})); return now; } template class Dijkstra { public: vector>> vertexs; B Cost_Function; Dijkstra(int n, B cost) : Cost_Function(cost) { vertexs = vector>>(n, vector>{}); } ~Dijkstra() { vertexs.clear(); } void add_edge(int a, int b, A c) { vertexs[a].push_back(mp(b, c)); } vector build_result(int StartPoint) { vector dist(vertexs.size(), 2e18); dist[StartPoint] = 0; priority_queue, vector>, greater>> next; next.push(make_pair(0, StartPoint)); while (next.empty() == false) { pair now = next.top(); next.pop(); if (dist[now.second] != now.first) continue; for (auto x : vertexs[now.second]) { ll now_cost = now.first + Cost_Function(x.second); if (dist[x.first] > now_cost) { dist[x.first] = now_cost; next.push(mp(now_cost, x.first)); } } } return dist; } }; class Dinic { public: struct edge { int to; int cap; int rev; }; vector> Graph; vector level; vector itr; Dinic(int n) { Graph = vector>(n, vector()); } void add_edge(int a, int b, int cap) { Graph[a].push_back(edge{ b, cap ,(int)Graph[b].size() }); Graph[b].push_back(edge{ a,0,(int)Graph[a].size() - 1 }); } void bfs(int s) { level = vector(Graph.size(), -1); level[s] = 0; queue next; next.push(s); while (next.empty() == false) { int now = next.front(); next.pop(); for (auto x : Graph[now]) { if (x.cap == 0) continue; if (level[x.to] == -1) { level[x.to] = level[now] + 1; next.push(x.to); } } } } int dfs(int now, int goal, int val) { if (goal == now) return val; for (int& i = itr[now]; i < (int)Graph[now].size(); ++i) { edge& target = Graph[now][i]; if (target.cap > 0 && level[now] < level[target.to]) { int d = dfs(target.to, goal, min(val, target.cap)); if (d > 0) { target.cap -= d; Graph[target.to][target.rev].cap += d; return d; } } } return 0; } int run(int s, int t) { int ans = 0; int f = 0; while (bfs(s), level[t] >= 0) { itr = vector(Graph.size(), 0); while ((f = dfs(s, t, 1e9)) > 0) { ans += f; } } return ans; } }; class HLDecomposition { public: vector> vertexs; vector depth; vector backs; vector connections; vector zip, unzip; HLDecomposition(int n) { vertexs = vector>(n, vector()); depth = vector(n); zip = vector(n); unzip = zip; } void add_edge(int a, int b) { vertexs[a].push_back(b); vertexs[b].push_back(a); } int depth_dfs(int now, int back) { depth[now] = 0; for (auto x : vertexs[now]) { if (x == back) continue; depth[now] = max(depth[now], 1 + depth_dfs(x, now)); } return depth[now]; } void dfs(int now, int backing) { zip[now] = backs.size(); unzip[backs.size()] = now; backs.push_back(backing); int now_max = -1; int itr = -1; for (auto x : vertexs[now]) { if (depth[x] > depth[now]) continue; if (now_max < depth[x]) { now_max = depth[x]; itr = x; } } if (itr == -1) return; connections.push_back(connections.back()); dfs(itr, backing); for (auto x : vertexs[now]) { if (depth[x] > depth[now]) continue; if (x == itr) continue; connections.push_back(zip[now]); dfs(x, backs.size()); } return; } void build() { depth_dfs(0, -1); connections.push_back(-1); dfs(0, -1); } vector> query(int a, int b) { a = zip[a]; b = zip[b]; vector> ans; while (backs[a] != backs[b]) { if (a < b) swap(a, b); ans.push_back(mp(backs[a], a + 1)); a = connections[a]; } if (a > b) swap(a, b); ans.push_back(mp(a, b + 1)); return ans; } int lca(int a, int b) { a = zip[a]; b = zip[b]; while (backs[a] != backs[b]) { if (a < b) swap(a, b); a = connections[a]; } return unzip[min(a, b)]; } }; //by ei1333 //https://ei1333.github.io/luzhiled/snippets/structure/segment-tree.html template< typename Monoid > struct SegmentTree { using F = function< Monoid(Monoid, Monoid) >; int sz; vector< Monoid > seg; const F f; const Monoid M1; SegmentTree(int n, const F f, const Monoid& M1) : f(f), M1(M1) { sz = 1; while (sz < n) sz <<= 1; seg.assign(2 * sz + 1, M1); } void set(int k, const Monoid& x) { seg[k + sz] = x; } void build() { for (int k = sz - 1; k > 0; k--) { seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]); } } void update(int k, const Monoid& x) { k += sz; seg[k] = x; while (k >>= 1) { seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]); } } Monoid query(int a, int b) { Monoid L = M1, R = M1; for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if (a & 1) L = f(L, seg[a++]); if (b & 1) R = f(seg[--b], R); } return f(L, R); } Monoid operator[](const int& k) const { return seg[k + sz]; } template< typename C > int find_subtree(int a, const C& check, Monoid& M, bool type) { while (a < sz) { Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]); if (check(nxt)) a = 2 * a + type; else M = nxt, a = 2 * a + 1 - type; } return a - sz; } template< typename C > int find_first(int a, const C& check) { Monoid L = M1; if (a <= 0) { if (check(f(L, seg[1]))) return find_subtree(1, check, L, false); return -1; } int b = sz; for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if (a & 1) { Monoid nxt = f(L, seg[a]); if (check(nxt)) return find_subtree(a, check, L, false); L = nxt; ++a; } } return -1; } template< typename C > int find_last(int b, const C& check) { Monoid R = M1; if (b >= sz) { if (check(f(seg[1], R))) return find_subtree(1, check, R, true); return -1; } int a = sz; for (b += sz; a < b; a >>= 1, b >>= 1) { if (b & 1) { Monoid nxt = f(seg[--b], R); if (check(nxt)) return find_subtree(b, check, R, true); R = nxt; } } return -1; } }; template< typename Monoid, typename OperatorMonoid = Monoid > struct LazySegmentTree { using F = function< Monoid(Monoid, Monoid) >; using G = function< Monoid(Monoid, OperatorMonoid) >; using H = function< OperatorMonoid(OperatorMonoid, OperatorMonoid) >; int sz, height; vector< Monoid > data; vector< OperatorMonoid > lazy; const F f; const G g; const H h; const Monoid M1; const OperatorMonoid OM0; LazySegmentTree(int n, const F f, const G g, const H h, const Monoid& M1, const OperatorMonoid OM0) : f(f), g(g), h(h), M1(M1), OM0(OM0) { sz = 1; height = 0; while (sz < n) sz <<= 1, height++; data.assign(2 * sz, M1); lazy.assign(2 * sz, OM0); } void set(int k, const Monoid& x) { data[k + sz] = x; } void build() { for (int k = sz - 1; k > 0; k--) { data[k] = f(data[2 * k + 0], data[2 * k + 1]); } } inline void propagate(int k) { if (lazy[k] != OM0) { lazy[2 * k + 0] = h(lazy[2 * k + 0], lazy[k]); lazy[2 * k + 1] = h(lazy[2 * k + 1], lazy[k]); data[k] = reflect(k); lazy[k] = OM0; } } inline Monoid reflect(int k) { return lazy[k] == OM0 ? data[k] : g(data[k], lazy[k]); } inline void recalc(int k) { while (k >>= 1) data[k] = f(reflect(2 * k + 0), reflect(2 * k + 1)); } inline void thrust(int k) { for (int i = height; i > 0; i--) propagate(k >> i); } void update(int a, int b, const OperatorMonoid& x) { thrust(a += sz); thrust(b += sz - 1); for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) { if (l & 1) lazy[l] = h(lazy[l], x), ++l; if (r & 1) --r, lazy[r] = h(lazy[r], x); } recalc(a); recalc(b); } Monoid query(int a, int b) { thrust(a += sz); thrust(b += sz - 1); Monoid L = M1, R = M1; for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) { if (l & 1) L = f(L, reflect(l++)); if (r & 1) R = f(reflect(--r), R); } return f(L, R); } Monoid operator[](const int& k) { return query(k, k + 1); } template< typename C > int find_subtree(int a, const C& check, Monoid& M, bool type) { while (a < sz) { propagate(a); Monoid nxt = type ? f(reflect(2 * a + type), M) : f(M, reflect(2 * a + type)); if (check(nxt)) a = 2 * a + type; else M = nxt, a = 2 * a + 1 - type; } return a - sz; } template< typename C > int find_first(int a, const C& check) { Monoid L = M1; if (a <= 0) { if (check(f(L, reflect(1)))) return find_subtree(1, check, L, false); return -1; } thrust(a + sz); int b = sz; for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if (a & 1) { Monoid nxt = f(L, reflect(a)); if (check(nxt)) return find_subtree(a, check, L, false); L = nxt; ++a; } } return -1; } template< typename C > int find_last(int b, const C& check) { Monoid R = M1; if (b >= sz) { if (check(f(reflect(1), R))) return find_subtree(1, check, R, true); return -1; } thrust(b + sz - 1); int a = sz; for (b += sz; a < b; a >>= 1, b >>= 1) { if (b & 1) { Monoid nxt = f(reflect(--b), R); if (check(nxt)) return find_subtree(b, check, R, true); R = nxt; } } return -1; } }; class KMP { public: vector table; vector Pattern; KMP(vector a) { build(a); } void build(vector a) { Pattern = a; table = vector(a.size() + 1, -1); int j = -1; for (int i = 0; i < a.size(); ++i) { while (j >= 0 && Pattern[i] != Pattern[j]) { j = table[j]; } table[i + 1] = ++j; } return; } vector search(vector a) { vector ans; for (int i = 0, k = 0; i < a.size(); ++i) { while (k >= 0 && a[i] != Pattern[k]) k = table[k]; ++k; if (k >= Pattern.size()) { ans.push_back(i - Pattern.size() + 1); k = table[k]; } } return ans; } }; unsigned long xor128() { static unsigned long x = 123456789, y = 362436069, z = 521288629, w = 88675123; unsigned long t = (x ^ (x << 11)); x = y; y = z; z = w; return (w = (w ^ (w >> 19)) ^ (t ^ (t >> 8))); } void init() { iostream::sync_with_stdio(false); cout << fixed << setprecision(10); } #define int ll void solve() { int a, b; cin >> a >> b; int hoge = 0; REP(t, 100000) { hoge = a * hoge + b; if (abs(hoge) > abs(b)) { cout << -1 << endl; return; } if (hoge == 0) { cout << t + 1 << endl; return; } } } #undef int int main() { init(); solve(); }