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 kb = new Scanner(System.in);
		int n = kb.nextInt();
		int m = kb.nextInt();
		int t = kb.nextInt();
		
		long result = 0;
		
		for(int i = 4; i < t; i++) {
			result += helper(n, i) * helper(m, t - i);
		}
		System.out.print(result);
	}
	
	public static long helper(int n, int m) {
		long result = 1;
		
		for(int i = 0; i < m; i++) {
			result *= (n - i);
			result /= (i + 1);
		}
		return result;
	}

}
