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.*;
import java.math.*;

public class worldtheatre {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n, m, t;

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

		BigInteger answer;
		answer = c(n+m,t).subtract(c(n,t)).subtract(c(n,0).multiply(c(m,t))).subtract(c(n,1).multiply(c(m,t-1))).subtract(c(n,2).multiply(c(m,t-2))).subtract(c(n,3).multiply(c(m,t-3)));
		System.out.println(answer);
	}

	public static BigInteger c(int n,int k) {
		if(k>n) {
			return new BigInteger("0");
		}
		if(n-k<k) {
			return c(n,n-k);
		}
		
		BigInteger res = new BigInteger("1");
		for(int i = 0; i<k; i++) {
			res = res.multiply(BigInteger.valueOf(n-i));
		}

		for(int i = 1; i<=k;i++) {
			res = res.divide(BigInteger.valueOf(i));
		}

		return res;
	}
}