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 {
	public static void main(String[] args) throws Exception {
		Scanner in = new Scanner(System.in);
		int a = in.nextInt(), b = in.nextInt(), c = in.nextInt();
		long sum =0;
		for(int x=4;x<=a;x++) {
			if(c-x<1) break;
			sum+=choose(a,x)*choose(b,c-x);
		}
		System.out.println(sum);
	}
	static long choose(int a, int b) {
		if(b>a) return 0;
		if(b*2>a) return choose(a,a-b);
		long ret = 1;
		for(long x =1;x<=b;x++) {
			ret*=(a-x+1);
			ret/=x;
		}
		return ret;
	}
}
