#include <bits/stdc++.h>

using LL = long long;

const int N = 4e6 + 7;
const int MOD = 1e9 + 7;

int p, q, r, fac[N], ifc[N];
int a[N];

int pow(int x, int y) {
  int ret = 1;
  while(y) {
    if(y & 1)
      ret = 1LL * ret * x % MOD;
    x = 1LL * x * x % MOD;
    y >>= 1;
  }
  return ret;
}

int com(int x, int y) {
  return 1LL * fac[x] * ifc[y] % MOD * ifc[x - y] % MOD;
}

int main() {

  fac[0] = 1;
  for(int i = 1; i < N; ++i)
    fac[i] = 1LL * fac[i - 1] * i % MOD;
  ifc[N - 1] = pow(fac[N - 1], MOD - 2);
  for(int i = N - 2; i >= 0; --i)
    ifc[i] = 1LL * ifc[i + 1] * (i + 1) % MOD;

  scanf("%d%d%d", &p, &q, &r);

  if(!p && !q && !r) {
    puts("1");
    return 0;
  }
  
  int m = p + q + r;
  a[0] = 1;
  for(int i = 0; i <= m + 1; ++i)
    a[i] = a[i] - (m + 1 - i & 1 ? -1 : 1) * com(m + 1, i);
  for(int i = 0; i <= m; ++i) {
    a[i] = 1LL * a[i] * ifc[2] % MOD;
    a[i + 1] = (a[i + 1] + a[i]) % MOD;
  }
  
  int ans = 0;
  for(int i = 1; i <= m; ++i)
    ans = (ans + 1LL * a[i] * com(i + p - 1, p) % MOD * com(i + q - 1, q) % MOD *
	   com(i + r - 1, r)) % MOD;
  
  printf("%d\n", (ans + MOD) % MOD);
  
  return 0;
}