const MOD: usize = 1e9 as usize + 7;

fn fact_inv(size: usize) -> (Vec<usize>, Vec<usize>) {
    let mut facts = vec![0usize; size+1];
    let mut fact_invs = vec![0usize; size+1];
    let mut invs = vec![0usize; size+1];
    facts[0] = 1;
    facts[1] = 1;
    fact_invs[0] = 1;
    fact_invs[1] = 1;
    invs[1] = 1;
    for i in 2..=size {
        facts[i] = facts[i-1] * i % MOD;
        invs[i] = MOD - invs[MOD % i] * (MOD / i) % MOD;
        fact_invs[i] = fact_invs[i - 1] * invs[i] % MOD;
    }
    (facts, fact_invs)
}

fn comb(n: usize, r: usize, facts: &Vec<usize>, fact_invs: &Vec<usize>) -> usize {
    facts[n] * fact_invs[r] % MOD * fact_invs[n-r] % MOD
}

fn main() {
    let mut abc = String::new();
    std::io::stdin().read_line(&mut abc).ok();
    let abc: Vec<usize> = abc.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let summary = abc.iter().sum::<usize>();
    let a = abc[0];
    let b = abc[1];
    let c = abc[2];

    let (facts, fact_invs) = fact_inv(summary+10);
    let mut p2s = vec![1usize; summary+1];
    for i in 0..summary {
        p2s[i+1] = p2s[i] * 2 % MOD;
    }
    let mut result = 0usize;
    for i in 1..=a {
        result += (p2s[a+b+c-i-1] - 1) * comb(a+b+c-i-2, a-i, &facts, &fact_invs) % MOD * comb(b+c-2, b-1, &facts, &fact_invs) % MOD;
        result %= MOD;
    }
    println!("{}", result);
}