/* **************************************************************** **************************************************************** -> Coded by Stavros Chryselis -> Visit my github for more solved problems over multiple sites -> https://github.com/StavrosChryselis -> Feel free to email me at stavrikios@gmail.com **************************************************************** **************************************************************** */ #include #include #include #define gc() getchar() #define MAXN 1000000 using namespace std; const long long MOD = 1000000007; long long fact[1000007]; long long N, A, B, D; inline long long modpow(long long base, long long exp, long long modulus) { long long result = 1; base %= modulus; while (exp > 0) { if (exp & 1) result = (result * base) % modulus; base = (base * base) % modulus; exp >>= 1; } return result; } inline bool finish() { char c = gc(); while (isspace(c)) c = gc(); if (c == EOF) { ungetc(c, stdin); return 1; } ungetc(c, stdin); return 0; } inline void pre() { int i; fact[0] = 1; for (i = 1; i <= MAXN; i++) { fact[i] = fact[i - 1] * i; fact[i] %= MOD; } } inline long long rev(long long num) { return modpow(num, MOD - 2, MOD); } inline long long ncr(long long n, long long k) { long long res = fact[n]; res *= rev(fact[k]); res %= MOD; res *= rev(fact[n - k]); res %= MOD; return res; } inline void init() { scanf("%lld %lld %lld %lld", &N, &A, &B, &D); } inline long long solve() { long long res = ncr(N, A); res *= modpow(ncr(B, D), A, MOD); res %= MOD; return res; } int main() { // freopen("input.txt", "r", stdin); pre(); while (!finish()) { init(); printf("%lld\n", solve()); } return 0; }