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;

public class TheWorldIsATheatre {
	
	static long nCk(long n , long k)
	{
		if(k>n)
			return 0;
		long ans = 1l;
		for(int i=1;i<=k;i++)
			ans= 1l*ans*(n-k+i)/i;
			
		return ans;
	}
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int t = sc.nextInt();
		
		long ans = 0;
		for(int i=1;i<=t-4;i++)
		{
			int x = t-i;
			ans = ans+ (1l* nCk(n,x)*nCk(m,i));
		}
		
		System.out.println(ans);
	}

}
