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 Main {

	static BigInteger fact(BigInteger n){
	
		BigInteger sum = BigInteger.ONE;
		for(int i=1 ; i<=n.intValue(); i++)
			sum = sum.multiply(BigInteger.valueOf(i));
	
		return sum;
	}
	
	static BigInteger cost(BigInteger n , BigInteger k){
		BigInteger temp;
		temp = fact(n).divide(fact(n.subtract(k)).multiply(fact(k)));
		return temp;
	}
	public static void main(String[] args) {
		
		
		Scanner scan = new Scanner(System.in);
		
		BigInteger n,m,t,temp;
		n = scan.nextBigInteger();m = scan.nextBigInteger(); t = scan.nextBigInteger();
		if(n.intValue()>t.intValue()-1)
			temp = t.subtract(BigInteger.ONE);
		else
			temp = n;
		BigInteger sum =BigInteger.ZERO;
		
		while(temp.intValue()>=4 && t.subtract(temp).intValue()<=m.intValue()){
		
			sum = sum.add(cost(n,temp).multiply(cost(m , t.subtract(temp))));
			temp = temp.subtract(BigInteger.ONE);
		}
		System.out.println(sum);

	}

}
