#include using namespace std; using lint = long long; using pint = pair; using plint = pair; struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_; #define ALL(x) (x).begin(), (x).end() #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template void ndarray(vector& vec, const V& val, int len) { vec.assign(len, val); } template void ndarray(vector& vec, const V& val, int len, Args... args) { vec.resize(len), for_each(begin(vec), end(vec), [&](T& v) { ndarray(v, val, args...); }); } template bool chmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; } template bool chmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; } int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); } template pair operator+(const pair &l, const pair &r) { return make_pair(l.first + r.first, l.second + r.second); } template pair operator-(const pair &l, const pair &r) { return make_pair(l.first - r.first, l.second - r.second); } template vector sort_unique(vector vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; } template istream &operator>>(istream &is, vector &vec) { for (auto &v : vec) is >> v; return is; } template ostream &operator<<(ostream &os, const vector &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; } template ostream &operator<<(ostream &os, const array &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; return os; } #if __cplusplus >= 201703L template istream &operator>>(istream &is, tuple &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; } template ostream &operator<<(ostream &os, const tuple &tpl) { std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os; } #endif template ostream &operator<<(ostream &os, const deque &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; } template ostream &operator<<(ostream &os, const set &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const unordered_set &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const multiset &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const unordered_multiset &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const pair &pa) { os << '(' << pa.first << ',' << pa.second << ')'; return os; } template ostream &operator<<(ostream &os, const map &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const unordered_map &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; } #ifdef HITONANODE_LOCAL const string COLOR_RESET = "\033[0m", BRIGHT_GREEN = "\033[1;32m", BRIGHT_RED = "\033[1;31m", BRIGHT_CYAN = "\033[1;36m", NORMAL_CROSSED = "\033[0;9;37m", RED_BACKGROUND = "\033[1;41m", NORMAL_FAINT = "\033[0;2m"; #define dbg(x) cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << endl #else #define dbg(x) (x) #endif // Calculate log_A B (MOD M) (baby-step gian-step) // DiscreteLogarithm dl(M, A); // lint ans = dl.log(B); // Complexity: O(M^(1/2)) for each query // Verified: // Constraints: 0 <= A < M, B < M, 1 <= M <= 1e9 (M is not limited to prime) struct DiscreteLogarithm { using lint = long long int; int M, stepsize; lint baby_a, giant_a, g; std::unordered_map baby_log_dict; lint inverse(lint a) { lint b = M / g, u = 1, v = 0; while (b) { lint t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); } u %= M / g; return u >= 0 ? u : u + M / g; } DiscreteLogarithm(int mod, int a_new) : M(mod), baby_a(a_new % mod), giant_a(1) { g = 1; while (std::__gcd(baby_a, M / g) > 1) g *= std::__gcd(baby_a, M / g); stepsize = 32; // lg(MAX_M) while (stepsize * stepsize < M / g) stepsize++; lint now = 1 % (M / g), inv_g = inverse(baby_a); for (int n = 0; n < stepsize; n++) { if (!baby_log_dict.count(now)) baby_log_dict[now] = n; (now *= baby_a) %= M / g; (giant_a *= inv_g) %= M / g; } } // log(): returns the smallest nonnegative x that satisfies a^x = b mod M, or -1 if there's no solution lint log(lint b) { b %= M; lint acc = 1 % M; for (int i = 0; i < stepsize; i++) { if (acc == b) return i; (acc *= baby_a) %= M; } if (b % g) return -1; // No solution lint now = b * giant_a % (M / g); for (lint q = 1; q <= M / stepsize + 1; q++) { if (baby_log_dict.count(now)) return q * stepsize + baby_log_dict[now]; (now *= giant_a) %= M / g; } return -1; } }; // Solve ax+by=gcd(a, b) lint extgcd(lint a, lint b, lint &x, lint &y) { lint d = a; if (b != 0) d = extgcd(b, a % b, y, x), y -= (a / b) * x; else x = 1, y = 0; return d; } // Calc a^(-1) (MOD m) lint mod_inverse(lint a, lint m) { lint x, y; extgcd(a, m, x, y); return (m + x % m) % m; } lint solve(int N) { while (N % 2 == 0) N /= 2; while (N % 5 == 0) N /= 5; DiscreteLogarithm dl(N, 10); return dl.log(mod_inverse(10, N)) + 1; } int main() { int T; cin >> T; while (T--) { int N; cin >> N; cout << solve(N) << '\n'; } }