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 org.omg.CORBA.INTERNAL;

import java.util.*;

public class Sol {
    public static int n;
    public static int m;
    public static int t;
    public static long ans = 0;
    public static long finalans = 0;
    public static long[]fact = new long[16];
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
         n = input.nextInt();
         m = input.nextInt();
         t = input.nextInt();
        fact[0] = 1;
        fact[1] = 1;

        for(int i=4 ; i<=n ; i++){
            ans = 1;
            if ( t-i >= 1 && t-i <= m){
             finalans += (binomial(n,i) * binomial(m,t-i));
            }
        }

        System.out.println(finalans);
    }

    public static long binomial(int n, int k){
        long result = 1;
        for ( int i = 0; i < k; i ++){
            result *= (n-i);
            result /= (i+1);
        }
        return result ;
    }

}
