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;
//codeforces 131C
public class compute{

	static long choose(int n, int k) {
		long res = 1;
		for(int i =1; i<=k; i++) {
			res *= n;
			res /= i;
			n--;
		}
		return res;
	}

	public static void main(String[] args) {

		int n, m, t;
		boolean debug = false;
		Scanner in = new Scanner(System.in);

		n = in.nextInt();
		m = in.nextInt();
		t = in.nextInt();

		int j, i;
		long ans = 0;

		for(j=1; ( j<=m && j<=(t-4) ); j++) {
			if(debug) System.out.println("j = "+j);
			i=t-j;
			if(i<=n) {
				if(debug) System.out.println("i = "+i);
				ans += ( ( choose(n,i) )*( choose(m,j) ) );

			}
		}

		System.out.println(ans);

	}



}






