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_131_The_World_Is_a_Threater {
	
	
	public static BigInteger factorial(int a,int b){
		BigInteger answer=BigInteger.valueOf(1);
		int i;
		//System.out.println("a="+a);
		//System.out.println("b="+b);
		for(i=1;i<=b;i++){
			answer=answer.multiply(BigInteger.valueOf(a-i+1));
			answer=answer.divide(BigInteger.valueOf(i));
		}
		return answer;
	}
	
	public static void main(String[] args){
		Scanner input=new Scanner(System.in);
		int m=input.nextInt();
		int n=input.nextInt();
		int t=input.nextInt();
		int j;
		BigInteger answer1=BigInteger.valueOf(0);
		BigInteger answer2=BigInteger.valueOf(0);
		BigInteger result=BigInteger.valueOf(0);
		for(j=1;j<=t-4;j++){
			answer1=factorial(m,t-j);
			answer2=factorial(n,j);
			//System.out.println("answer1="+answer1);
			//System.out.println("answer2="+answer2);
			answer1=answer1.multiply(answer2);
			result=result.add(answer1);
		}
		System.out.println(result);
	}
}
