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.Scanner;

public class MainF{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long x = sc.nextInt();
		long y = sc.nextInt();
		long a = sc.nextInt();
	
			long sum = 0;
			for(long i = 0; i <= a; i++){
				long r = i, s = a-i;
				if(r>=4 && s>=1 && r <= x && s <= y){
					sum = sum + choose(x,r)*choose(y,s);
				}
			}		
			
			System.out.println(sum);
		
		
		
		sc.close();
	}
	
	private static long choose(long n, long k){
		long i, res = 1;
		
		for(i = 0; i < Math.min(k, n - k); i++){
			res = res*  (n-i) / (i+1);
		}
		return res;
	}

}