#include<iostream>
using namespace std;
#define int long long
const int N = 4e6 + 5;
const int mod = 1e9 + 7;

int p,q,r,fac[N],inv[N],ans,a[N];

int qpow(int a,int b)
{
	int res = 1;
	while(b)
	{
		if(b & 1) res = res * a % mod;
		a = a * a % mod; b >>= 1;
	}
	return res;
}

const int inv2 = qpow(2,mod-2);

int c(int x,int y)
{
	if(x < 0 || y < 0 || x < y) return 0;
	return fac[x] * inv[y] % mod * inv[x-y] % mod;
}

signed main()
{
	cin >> p >> q >> r;
	if(p == 0 && q == 0 && r == 0) {cout << 1 << '\n'; return 0;}
	fac[0] = 1; for(int i=1;i<N;i++) fac[i] = fac[i-1] * i % mod;
	inv[N-1] = qpow(fac[N-1],mod-2); for(int i=N-2;i>=0;i--) inv[i] = inv[i+1] * (i + 1) % mod;
	for(int i=0;i<=p+q+r+1;i++)
	{
		a[i] = c(p+q+r+1,i) * ((p + q + r - i) & 1 ? -1 : 1);
		// cout << a[i] << " ";
		if(i) a[i] = (a[i] + a[i-1]) * inv2 % mod;
		else a[i] = (a[i] + 1) * inv2 % mod;
		// cout << a[i] << " ";
		ans = (ans + a[i] * c(i + p - 1, p) % mod * c(i + q - 1, q) % mod * c(i + r - 1, r) % mod + mod) % mod;
	}
	cout << ans << '\n';
	return 0;
}