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

inf = 10 ** 6
fact = [1] * inf
fact_inv = [1] * inf
P = 10 ** 9 + 7
for i in range(2,inf):
    fact[i] = fact[i-1] * i % P
fact_inv[-1] = pow(fact[-1],P-2,P)
for i in range(inf-2,1,-1):
    fact_inv[i] = fact_inv[i+1] * (i+1) % P
ans = 0
for i in  range(1,a+1):
    M = a + b + c - 1 - i
    tmp = fact[M-1] * fact_inv[c-1] % P * fact_inv[b-1] % P * fact_inv[a - i] % P
    tmp = (pow(2,M,P)-1) * tmp % P
    ans = (ans + tmp) % P
print(ans)