// yukicoder: No.442 和と積 // 2019.4.17 bal4u #include #include #define SIZE 50 long long factor[3][SIZE]; int power[3][SIZE]; int sz[3]; int ptbl[] = { 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997, 0 }; int prime_factor(int id, long long n) { int i, d, size; int *pp; size = 0; if ((n & 1) == 0) { factor[id][size] = 2; do n >>= 1, power[id][size]++; while ((n & 1) == 0); size++; } for (pp = ptbl; n > 1 && *pp > 0; pp++) { if (n % *pp) continue; d = *pp; factor[id][size] = d; do n /= d, power[id][size]++; while (n % d == 0); size++; } if (n > 1) { int b = (int)sqrt((double)n); for (i = 1009; n > 1; i += 2) { if (i > b) { factor[id][size] = n, power[id][size++] = 1; break; } if (n % i == 0) { factor[id][size] = i; do n /= i, power[id][size]++; while (n % i == 0); size++; } } } return size; } int f[SIZE]; int main() { int i, j; long long A, B, a, b, a2, b2, ans; scanf("%lld%lld", &A, &B); if (A == B) { if (A & 1) ans = A; else ans = A << 1; printf("%lld\n", ans); return 0; } a = A, b = B; a2 = 1; while ((a & 1) == 0) a2 <<= 1, a >>= 1; b2 = 1; while ((b & 1) == 0) b2 <<= 1, b >>= 1; if (a2 < b2) ans = a2; else ans = b2; if (ans > 0 && (a > 0x7fffffffffff || b > 0xffffffffffff)) { printf("%lld\n", ans); return 0; } sz[0] = prime_factor(0, A); sz[1] = prime_factor(1, B); sz[2] = prime_factor(2, A+B); i = j = 0; while (i < sz[0] && j < sz[1]) { while (factor[1][j] > factor[0][i] && i < sz[0]) i++; while (factor[1][j] < factor[0][i] && j < sz[1]) j++; if (i < sz[0] && j < sz[1] && factor[0][i] == factor[1][j]) { power[0][i] += power[1][j], factor[1][j] = 0; i++, j++; } } ans = 1; i = j = 0; while (i < sz[0] && j < sz[2]) { while (factor[2][j] > factor[0][i] && i < sz[0]) i++; while (factor[2][j] < factor[0][i] && j < sz[2]) j++; if (i < sz[0] && j < sz[2] && factor[0][i] == factor[2][j]) { if (power[0][i] > power[2][j]) power[0][i] = power[2][j]; while (power[0][i]--) ans *= factor[0][i]; } i++, j++; } i = j = 0; while (i < sz[1] && j < sz[2]) { while (factor[2][j] > factor[1][i] && i < sz[1]) i++; while (factor[2][j] < factor[1][i] && j < sz[2]) j++; if (i < sz[1] && j < sz[2] && factor[1][i] == factor[2][j]) { if (power[1][i] > power[2][j]) power[1][i] = power[2][j]; while (power[1][i]--) ans *= factor[1][i]; } i++, j++; } printf("%lld\n", ans); return 0; }