import sys read = sys.stdin.buffer.read readline = sys.stdin.buffer.readline readlines = sys.stdin.buffer.readlines import numpy as np X,Y,Z = map(int,read().split()) MOD = 10 ** 9 + 7 def cumprod(arr,MOD): L = len(arr); Lsq = int(L**.5+1) arr = np.resize(arr,Lsq**2).reshape(Lsq,Lsq) for n in range(1,Lsq): arr[:,n] *= arr[:,n-1]; arr[:,n] %= MOD for n in range(1,Lsq): arr[n] *= arr[n-1,-1]; arr[n] %= MOD return arr.ravel()[:L] def make_fact(U,MOD): x = np.arange(U,dtype=np.int64); x[0] = 1 fact = cumprod(x,MOD) x = np.arange(U,0,-1,dtype=np.int64); x[0] = pow(int(fact[-1]),MOD-2,MOD) fact_inv = cumprod(x,MOD)[::-1] return fact,fact_inv def make_power(a,L,MOD): B = L.bit_length() x = np.empty(1 + (1<> 15 gl = g & (1 << 15) - 1; gh = g >> 15 conv = lambda f,g: ifft(fft(f,fft_len) * fft(g,fft_len))[:L] x = conv(fl,gl) % MOD y = conv(fl+fh,gl+gh) % MOD z = conv(fh,gh) % MOD a, b, c = map(lambda x: (x + .5).astype(np.int64), [x,y,z]) return (a + ((b - a - c) << 15) + (c << 30)) % MOD def f(X,Y,Z): if X==Y==Z==0: return 1 """ (2-2P/1-2P)^{Z+1} * (1/4-4P) の x^Xy^Y の係数を返す """ N = Z + 1 U = X + Y + 100 # 分子 A = fact[N] * fact_inv[:N+1] % MOD * fact_inv[:N+1][::-1] A[1::2] *= (-1); A %= MOD A = A[:U]; A *= power2[N]; A %= MOD # 分母の逆 B = fact[N-1:N+U-1] * fact_inv[N-1] % MOD * fact_inv[:U] % MOD B *= power2[:U]; B %= MOD C = fft_convolve(A,B)[:U] # 4 - 4P で割る C *= (MOD+1)//4; C %= MOD; np.cumsum(C,out=C); C %= MOD # 各 n に対して、P^n = (x + y - xy)^n での x^Xy^Y の係数を求める L = max(X,Y); R = X+Y x = np.zeros(R-L+1,np.int64) x = fact[L:R+1].copy() x *= fact_inv[L-Y:R-Y+1]; x %= MOD x *= fact_inv[L-X:R-X+1]; x %= MOD x *= fact_inv[0:X+Y-L+1][::-1]; x %= MOD x[(R+L+1)%2::2] *= (-1) return (x * C[L:R+1] % MOD).sum() % MOD # 3, 13, 512, 882313923 # f(1,1,0), f(1,1,1), f(10,0,0), f(31,53,6000), f(53,31,6000) # f(6000,31,53), f(6000,53,31) answer = f(X,Y,Z) print(answer)