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 C131 {
	static final int MAXN = 35;
	static long nCr[][], count = 0;
	
	public static void main(String[] args) {
		preCompute();
		
		Scanner in = new Scanner(System.in);
		int n = ni(in), m = ni(in), t = ni(in);
		for (int a = 0; a <= t; a++) {
			int b = t - a;
			if (a >= 4 && a <= n && b >= 1 && b <= m) count += nCr[n][a]*nCr[m][b];
		}
		System.out.println(count);
	}
	
	private static void preCompute() {
		nCr = new long[MAXN][MAXN];
		
		for (int i = 0; i < MAXN; i++) nCr[i][0] = nCr[i][i] = 1;
		for (int i = 1; i < MAXN; i++) nCr[0][i] = 0;
		
		for (int i = 1; i < MAXN; i++) {
			for (int j = 1; j < MAXN; j++)
				nCr[i][j] = nCr[i-1][j-1] + nCr[i-1][j];
		}
	}
	
	private static int ni(Scanner in) { return in.nextInt(); }
}
