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

MOD = 10**9 + 7
N = a+b+c

fact = [1]*(N+1)
rfact = [1]*(N+1)
r = 1
for i in range(1, N+1):
  fact[i] = r = r * i % MOD
rfact[N] = r = pow(fact[N], MOD-2, MOD)
for i in range(N, 0, -1):
  rfact[i-1] = r = r * i % MOD

ans = 0
for k in range(1, a+1):
    ans += fact[a+b+c-k-2] * rfact[a-k] * rfact[b+c-2] * (pow(2, a+b+c-k-1, MOD)-1) % MOD
ans = ans * fact[b+c-2] * rfact[b-1] * rfact[c-1] % MOD
print(ans)