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.io.*;
public class Main {
	public static void main(String[] args)throws IOException {
		BufferedReader in = new BufferedReader ( new InputStreamReader ( System.in ) ) ;
		String IN = in.readLine(); 
		int n = Integer.parseInt(IN.split(" ")[0]) , m = Integer.parseInt(IN.split(" ")[1]) ,
		t = Integer.parseInt(IN.split(" ")[2]) ;
		long ANS = 0 ;
		for ( int i = 4 ; i < t ; i ++ ) ANS += C(n,i) * C(m,t-i) ;
		System.out.println(ANS);
	}
	static long C ( int n , int p ){
		long ret = 1 ;
		for ( int i = 0 ; i < p ; i ++ ){
			ret *= (n-i) ;
			ret /= (i+1) ;
		}
		return ret ;
	}
}
