#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
#define DUMP(x)  cout << #x << " = " << (x) << endl;
#define FOR(i, m, n) for(ll i = m; i < n; i++)
#define IFOR(i, m, n) for(ll i = n - 1; i >= m; i-- )
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
#define FOREACH(x,a) for(auto& (x) : (a) )
#define ALL(v) (v).begin(), (v).end()
#define SZ(x) ll(x.size())

/* 二項係数 C(n,k) mod p を計算 */
const int MOD = 1000000007;
const int MAX = 501000;
long long fac[MAX], finv[MAX], inv[MAX];

void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++){
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}

long long COM(int n, int k){
  if (n < k) return 0;
  if (n < 0 || k < 0) return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

ll modpow(ll a , ll b, ll m){
  if (b == 0) return 1;
  ll ret;
  if (b%2 == 0){
    ll  t = modpow(a, b/2, m)%m;
    ret = t*t %m;
  }else{
    ll t = modpow(a, (b-1)/2,m)%m;
    ret = a*t %m * t % m;
  }
  ret %= m;
  return ret;
}
int main(){
  COMinit();
  ll a,b,c; cin >> a >> b >> c;
  ll ans = 0;
  ll N = a+b+c;
  //d:yの左端bit
  FOR(d,N-a-1,N-1){
    ll t = COM(d-1,b-1) * COM(d-b,c-1) % MOD;
    (ans += (t * (MOD+modpow(2,d,MOD)-1) % MOD) ) %= MOD;
  }
  cout << ans << endl;
}