#include <bits/stdc++.h>
using namespace std;
const int MD = 1e9 + 7;
const int MX = 3000005;
long long f[MX], g[MX], p[MX];
long long pw(long long x, long long y) {
    long long r = 1;
    while (y) {
        if (y & 1) r = r * x % MD;
        x = x * x % MD;
        y >>= 1;
    }
    return r;
}
long long C(int n, int m) {
    if (m < 0 || m > n) return 0;
    return f[n] * g[m] % MD * g[n - m] % MD;
}
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int a, b, c;
    cin >> a >> b >> c;
    int n = a + b + c;
    f[0] = 1;
    p[0] = 1;
    for (int i = 1; i <= n; ++i) {
        f[i] = f[i - 1] * i % MD;
        p[i] = p[i - 1] * 2 % MD;
    }
    g[n] = pw(f[n], MD - 2);
    for (int i = n - 1; i >= 0; --i) {
        g[i] = g[i + 1] * (i + 1) % MD;
    }
    long long ans = 0;
    long long cf = C(b + c - 2, b - 1);
    for (int k = 0; k < a; ++k) {
        int i = b + c - 1 + k;
        long long tm = C(b + c - 2 + k, b + c - 2);
        long long vl = (p[i] - 1 + MD) % MD;
        ans = (ans + tm * vl) % MD;
    }
    ans = ans * cf % MD;
    cout << ans << endl;
    return 0;
}