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);
		long[][] pascal = new long[61][61];

		int n = sc.nextInt();
		int m = sc.nextInt();
		int t = sc.nextInt();
		
		pascal[0][0] = 1;
		for (int i = 1; i <= 60; i++) {
			for (int j = 0; j <= i; j++) {
				if (j == 0 || j == i)
					pascal[i][j] = 1;
				else {
					pascal[i][j] = pascal[i - 1][j - 1] + pascal[i - 1][j];
				}
			}
		}

		long ans = 0;
		ans = ans + pascal[n + m][t];
		if (t <= m)
			ans = ans - pascal[m][t];
		if (t - 1 <= m)
			ans = ans - pascal[n][1] * pascal[m][t - 1];
		if (t - 2 <= m)
			ans = ans - pascal[n][2] * pascal[m][t - 2];
		if (t - 3 <= m)
			ans = ans - pascal[n][3] * pascal[m][t - 3];
		if (t <= n)
			ans = ans - pascal[n][t] * pascal[m][0];
		System.out.println(ans);
	}
}
