There are n boys and m girls attending a theatre club. To set a play "The Big Bang Theory", they need to choose a group containing exactly t actors containing no less than 4 boys and no less than one girl. How many ways are there to choose a group? Of course, the variants that only differ in the composition of the troupe are considered different.

Perform all calculations in the 64-bit type: long long for С/С++, int64 for Delphi and long for Java.

Input

The only line of the input data contains three integers n, m, t (4 ≤ n ≤ 30, 1 ≤ m ≤ 30, 5 ≤ t ≤ n + m).

Output

Find the required number of ways.

Please do not use the %lld specificator to read or write 64-bit integers in С++. It is preferred to use cin, cout streams or the %I64d specificator.

Examples

Input

5 2 5


Output

10


Input

4 3 5


Output

3


import java.math.BigInteger;
import java.util.Scanner;

public class C {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int b = sc.nextInt();
        int g = sc.nextInt();
        int t = sc.nextInt();
        BigInteger []p = new BigInteger[31];
        p[0] = p[1] = BigInteger.ONE;
        for (int i = 2; i < p.length; i++) {
            p[i] = p[i-1].multiply(new BigInteger(i+"")); 
        }
        long ans = 0;
        int k = t-5;
        for (int i = 0; i <=t-5; i++) {
            if (b >=k+4-i && g >= i+1){
                ans += p[b].divide(p[k+4-i].multiply(p[b-k+i-4])).multiply(p[g].divide(p[i+1].multiply(p[g-i-1]))).longValue();
            }
        }
        System.out.println(ans);
    }

}
