#include <iostream>

const long long MOD = (long long) 1e9 + 7;

const int NMAX = 312345;

long long fac[NMAX];
long long ifac[NMAX];
long long inv[NMAX];

int main() {
  fac[0] = fac[1] = ifac[0] = ifac[1] = inv[0] = inv[1] = 1;
  for (int i = 2; i < NMAX; ++i) {
    fac[i] = i * fac[i - 1] % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    ifac[i] = ifac[i - 1] * inv[i] % MOD;
  }
  int a, b, c;
  std::cin >> a >> b >> c;
  --a; --b; --c;
  long long ans = 0, p2 = 1;
  for (int i = 0; i < b + c + 1; ++i) p2 = p2 * 2 % MOD;
  for (int i = 0; i <= a; ++i) {
    ans = (ans + fac[i + b + c] * ifac[i] % MOD * (p2 - 1) % MOD) % MOD;
    p2 = p2 * 2 % MOD;
  }
  ans = ans * ifac[b] % MOD * ifac[c] % MOD;
  std::cout << ans << std::endl;
}