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.math.BigInteger;
import java.util.Scanner;


public class C {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int t = sc.nextInt();
		BigInteger ans = BigInteger.ZERO;
		for (int i = 4; i <= n; i++) {
			if (t-i >= 1 && t-i <= m) {
				ans = ans.add(C_n_m(n, i).multiply(C_n_m(m, t-i)));
			}
		}
		System.out.println(ans);
	}

	private static BigInteger C_n_m(int n, int m) {
		return fac(n).divide(fac(m).multiply(fac(n-m)));
	}

	private static BigInteger fac(int n) {
		if (n==0 || n==1)
			return BigInteger.ONE;
		return fac(n-1).multiply(BigInteger.valueOf(n));
	}
}
