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.util.*;
import java.math.*;

public class Main {

    /**
     * @param args
     */
    /*
     * Author : ngmq - FPT University
     */
    public static BigInteger chop(int a, int b){
        BigInteger ret = BigInteger.ONE;
        for(int i = 1; i <= b; ++i){
            ret = ret.multiply(BigInteger.valueOf(i));
        }
        for(int i = 1; i <= a; ++i){
            ret = ret.divide(BigInteger.valueOf(i));
        }
        for(int i = 1; i  <= b - a; ++i){
            ret = ret.divide(BigInteger.valueOf(i));
        }
        return ret;
    }
    

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int t = sc.nextInt();
        //System.out.println(n);
        //System.out.println(m);
        //System.out.println(t);
        BigInteger res = BigInteger.ZERO;
        for(int y = 1; y <= m; ++y){
            
            int x = t - y;
            if(x >= 4 && x <= n){
                res = res.add(chop(y,m).multiply(chop(x,n)));
                
            }
        }
        System.out.println(res);
    }

}
