import java.util.*;

public class Main {
    static final int MOD = 1000000007;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();
		Combination cmb = new Combination(a + b + c);
		long total = 0;
		for (int i = 1; i <= a; i++) {
		    int sum = a - i + b - 1 + c;
		    total += getValue(sum, c, cmb) * cmb.getComb(sum - c, a - i) % MOD;
		    total %= MOD;
		}
		System.out.println(total);
	}
	
	static long getValue(int x, int y, Combination cmb) {
	    if (y == 0) {
	        return 0;
	    }
	    return (pow(2, x) - 1 + MOD) % MOD * cmb.getComb(x - 1, y - 1) % MOD;
	}
	
	static long pow(long x, long p) {
	    if (p == 0) {
	        return 1;
	    }
	    if (p % 2 == 0) {
	        return pow(x * x % MOD, p / 2);
	    } else {
	        return pow(x, p - 1) * x % MOD;
	    }
	}
}

class Combination {
    static final int MOD = 1000000007;
    long[] fac;
    long[] finv;
    long[] inv;
    
    public Combination (int size) {
        fac = new long [size];
        finv = new long [size];
        inv = new long [size];
        fac[0] = 1;
        fac[1] = 1;
        finv[0] = 1;
        finv[1] = 1;
        inv[1] = 1;
        for (int i = 2; i < size; i++) {
            fac[i] = fac[i - 1] * i % MOD;
            inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
            finv[i] = finv[i - 1] * inv[i] % MOD;
        }
    }
    
    
    public long getComb(int n, int k) {
        if (n < k || n < 0 || k < 0) {
            return 0;
        }
        return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
    }
    
}