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.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner;

public class Demo {

	public static long combination(long n, long m){
		long ans = 1 ;
		for(int i=1 ; i <= m ; i++){
			ans = (ans * n) / i ;
			n-- ;
		}
		return ans ;
	}
	
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in) ;
		
		long n , m , k , cntN = 4 , cntM = 1 , ans = 0;
		n = scanner.nextLong();
		m = scanner.nextLong();
		k = scanner.nextLong();
		
		while(cntN <= n){
			long tempCombinationN = combination(n, cntN) ;
			cntM = 1 ;
			while(cntM <= m){
				long tempCombinationM = combination(m, cntM);
				if(cntN + cntM == k)
					ans += (tempCombinationN * tempCombinationM) ;
				cntM++ ;
			}
			cntN++ ;
		}
		
		System.out.println(ans);
		
		scanner.close();

	}

}
