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
//package Math.Codeforces;

import java.util.Scanner;

/**
 * @author Syed Ali.
 * @createdAt 30/03/2021, Tuesday, 19:56
 */
public class TheWorldIsATheatre {

	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int t = sc.nextInt();
		long ans = 0;
		for(int i = 4 ; i < t ; i++){
			ans += binomial(n,i) * binomial(m,t-i);
		}
		System.out.println(ans);
	}
	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 ;
	}
}
