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;
 
import java.math.BigInteger;

public class Main {
	
	public static BigInteger nCr(int n, int r) {
		if (n < r) return BigInteger.ZERO;
		int mini = (r < (n - r)) ? r : n - r;
		int maxi = (r < (n - r)) ? n - r : r;
		BigInteger res = BigInteger.ONE;
		for (int i = maxi + 1; i <= n; i++) res = res.multiply(BigInteger.valueOf(i));
		for (int i = 2; i <= mini; i++) res = res.divide(BigInteger.valueOf(i));
		return res;
	}
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		while (sc.hasNext()) { 
			BigInteger n = sc.nextBigInteger();
			BigInteger m = sc.nextBigInteger();
			BigInteger t = sc.nextBigInteger();
			BigInteger ans = BigInteger.ZERO;
			for (int i = 4, batas = n.intValue(), tt = t.intValue(), batas2 = m.intValue(); i <= batas; i++) {
				int boys = i, girls = tt - i;
				if (girls < 1) continue;
				ans = ans.add(nCr(batas, boys).multiply(nCr(batas2, girls)));
			}
			System.out.println(ans.toString());
		}
	}
}
