#include <bits/stdc++.h>
using namespace std;
#define int long long
#define MOD 1000000007

int kai[300010];

void init(){
    kai[0] = 1;
    for(int i = 1;i < 300010;i++) kai[i] = kai[i-1] * i % MOD;
}

int pow_mod(int n, int m){
    int ans = 1;
    while(m > 0){
        if(m & 1) ans = (ans * n) % MOD;
        n = (n * n) % MOD;
        m >>= 1;
    }
    return ans;
}

int combi(int n, int r){
    return kai[n] * pow_mod(kai[r], MOD-2) % MOD * pow_mod(kai[n-r], MOD-2) % MOD;
}

signed main(){
    int a, b, c;
    cin >> a >> b >> c;
    init();

    int num[300010] = {};
    int n = a + b + c;
    for(int i = 2;i < n;i++){
        if(i <= a + 1){
            num[i] = (combi(n-i-1, a-(i-1)) * combi(n-i-1-(a-(i-1)), b-1)) % MOD;
        }
    }

    for(int i = 3;i < n;i++){
        num[i] += num[i-1];
        num[i] %= MOD;
    }

    int ans = 0;
    for(int i = 2;i < n;i++){
        ans += (pow_mod(2, n-i-1) * num[i]) % MOD;
        ans %= MOD;
    }

    cout << ans << endl;
    return 0;
}