MOD = 10**9 + 7 a, b = map(int, input().split()) n, k = map(int, input().split()) max_needed = 2 * n - 2 # since for sum of squares, maximum comb is 2n-2 choose n-1 max_fact = max(max_needed, n-1) # for (n-1 choose k-1) and others fact = [1] * (max_fact + 1) for i in range(1, max_fact + 1): fact[i] = fact[i-1] * i % MOD inv_fact = [1] * (max_fact + 1) inv_fact[max_fact] = pow(fact[max_fact], MOD-2, MOD) for i in range(max_fact - 1, -1, -1): inv_fact[i] = inv_fact[i+1] * (i+1) % MOD def comb(n, k): if k < 0 or k > n: return 0 return fact[n] * inv_fact[k] % MOD * inv_fact[n - k] % MOD a_mod = a % MOD b_mod = b % MOD c1 = comb(n-1, k-1) c2 = comb(n-1, k-2) val = (a_mod * c1 + b_mod * c2) % MOD term1 = (a_mod * a_mod % MOD) * comb(2*n - 2, n-1) % MOD term2 = (2 * a_mod * b_mod % MOD) * comb(2*n - 2, n-2) % MOD term3 = (b_mod * b_mod % MOD) * comb(2*n - 2, n-1) % MOD sum_sq = (term1 + term2 + term3) % MOD print(val) print(sum_sq)