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 long getComb(long x ,long y) {
		long result = 1 ;
		for(int i = 1 ; i <= y ; i++) {
			result *= (x-i+1) ;
			result /= i ;
		}
		return result ;
	}
	public static void main(String [] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextInt();
		long m = sc.nextInt() ;
		long t = sc.nextInt() ;
		long result = 0 ;
		for(int i = 0 ; i <= t ; i ++) {
			if(t-i >= 4 && i >=1)
			result += ( getComb(n, t-i) * getComb(m, i));}
		System.out.println(result);
	}
	
}
