#!/Users/fushishita/.pyenv/shims/python

import sys

MOD = 1000000007
fact = [1]
rfact = [1]

def mod_inverse(x):
    return pow(x, MOD - 2, MOD)

def nCr(n, r):
    if r > n:
        return 0
    ret = fact[n]
    ret = ret * rfact[r] % MOD
    ret = ret * rfact[n - r] % MOD
    return ret

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

for i in range(1, n + 1):
    fact.append(fact[i - 1] * i % MOD)
    rfact.append(mod_inverse(fact[i]))

ans = 0
for i in range(1, a + 1):
    x = a + b + c - i - 1
    add = pow(2, x, MOD) - 1
    add = add * nCr(x - 1, c - 1) % MOD * nCr(x - 1 - (c - 1), b - 1) % MOD
    ans = (ans + add) % MOD
ans = (ans + MOD) % MOD
print('{}\n'.format(ans), end='')