#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const ll MOD = 1000000007;

ll modpow(ll x, ll n, ll mod = MOD) {
    ll res = 1;
    while (n > 0) {
        if (n & 1) res = res * x % mod;
        x = x * x % mod;
        n >>= 1;
    }
    return res;
}

const int MAXV = 300000;

ll f[MAXV + 1], fi[MAXV + 1];

void init(int n) {
    f[0] = 1;
    for (int i = 1; i <= n; i++) {
        f[i] = f[i-1]*i%MOD;
    }
    fi[n] = modpow(f[n], MOD - 2);
    for (int i = n; i > 0; i--) {
        fi[i-1] = fi[i] * i % MOD;
    }
}

ll comb3(int p, int q, int r) {
    return f[p + q + r] * fi[p] % MOD * fi[q] % MOD * fi[r] % MOD;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int a, b, c;
    cin >> a >> b >> c;
    int n = a + b + c;
    init(n);

    ll ans = 0;
    for (int m = n - 2; m >= 1; m--) {
        int aa = a - (n - m - 1);
        if (aa < 0) continue;
        int bb = b - 1;
        (ans += (modpow(2, m) + MOD - 1) % MOD * comb3(aa, bb, c - 1) % MOD) %= MOD;
    }
    cout << ans << "\n";
    return 0;
}