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
{
	public static void main(String[] args)
	{
		Scanner sc = new Scanner(System.in);
		
		int m = sc.nextInt();
		int n = sc.nextInt();
		int k = sc.nextInt();
		
		
		long sum = 0;
		for (int i = 4; i <= k-1; i++)
		{
			sum += (1l*nCr4(m, i)*nCr4(n, k-i));
		}
		
		System.out.println(sum);
		
	}
	
	static long nCr4(long N, long K)		// O(K)
	{
		if(K > N)
			return 0;
		long res = 1;
		for(int i = 1; i <= K; ++i)
			res = (N - K + i) * res / i;
		return res;
	}
}
