MOD = 10 ** 9 + 7
N = 500000
fact = [0 for _ in range(N)]
invfact = [0 for _ in range(N)]
fact[0] = 1
for i in range(1, N):
    fact[i] = fact[i - 1] * i % MOD

invfact[N - 1] = pow(fact[N - 1], MOD - 2, MOD)

for i in range(N - 2, -1, -1):
    invfact[i] = invfact[i + 1] * (i + 1) % MOD

def nCk(n, k):
    if k < 0 or n < k:
        return 0
    else:
        return (fact[n] * invfact[k] % MOD) * invfact[n - k] % MOD

def nPk(n, k):
    if k < 0 or n < k:
        return 0
    else:
        return fact[n] * invfact[n - k] % MOD

def nHk(n, k):
    if n == k == 0:
        return 1
    return nCk(n + k - 1, k)


a, b, c = map(int, input().split())

n = a + b + c
tot = 0
bi = 1
for _ in range(c - 1):
    tot += bi
    tot %= MOD
    bi <<= 1
    bi %= MOD

ans = 0
times = nCk(a + b - 1, b)
for i in range(c, n - 1):
    x = nCk(i - 1, c - 1)
    x *= times - nCk(i - c, b)
    x %= MOD
    ans += bi * x % MOD
    x *= pow(i - 1, MOD - 2, MOD) * (c - 1) % MOD
    x %= MOD
    ans += x * tot % MOD
    ans %= MOD

    tot += bi
    tot %= MOD
    bi <<= 1
    bi %= MOD

print(ans)