// #pragma GCC target("avx2") #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") #include #include using namespace std; using namespace atcoder; using mint = modint998244353; // using mint = modint1000000007; using ll = long long; using ull = unsigned long long; using ld = long double; using pii = pair; using pll = pair; using T = tuple; using G = vector>; #define rep(i, n) for (ll i = 0; i < (n); ++i) #define rep2(i, a, b) for (ll i = a; i < (b); ++i) #define rrep2(i, a, b) for (ll i = a-1; i >= (b); --i) #define rep3(i, a, b, c) for (ll i = a; i < (b); i+=c) #define rng(a) a.begin(),a.end() #define rrng(a) a.rbegin(),a.rend() #define popcount __builtin_popcount #define popcountll __builtin_popcountll #define fi first #define se second #define UNIQUE(v) sort(rng(v)), v.erase(unique(rng(v)), v.end()) #define MIN(v) *min_element(rng(v)) #define MAX(v) *max_element(rng(v)) #define SUM(v) accumulate(rng(v),0) #define IN(v, x) (find(rng(v),x) != v.end()) template bool chmin(T &a,T b){if(a>b){a=b;return 1;}else return 0;} template bool chmax(T &a,T b){if(a void printv(vector &v){rep(i,v.size())cout< void printvv(vector> &v){rep(i,v.size())rep(j,v[i].size())cout< extgcd(ll a, ll b) { if (b == 0) return {a, 1, 0}; ll g, x, y; tie(g, x, y) = extgcd(b, a%b); return {g, y, x-a/b*y}; } int main(){ ios::sync_with_stdio(false); cin.tie(nullptr); ll n, m; cin >> n >> m; ll g = gcd(n, m); n /= g, m /= g; cout << n << " " << m << endl; int cnt2 = 0, cnt5 = 0; while(m%2 == 0) m /= 2, cnt2++; while(m%5 == 0) m /= 5, cnt5++; if (m != 1){ cout << -1 << endl; return 0; } while(n%10 == 0) n /= 10; if (cnt2 < cnt5){ rep(i, cnt5 - cnt2){ n *= 2; n %= 10; } } else if(cnt2 > cnt5){ rep(i, cnt2 - cnt5){ n *= 5; n %= 10; } } cout << n%10 << endl; return 0; }