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.*;
import java.math.*;
public class Main{
	static BigInteger  c(int n,int k){
		BigInteger ans = BigInteger.valueOf(1);
		if (k>n) {
			ans = BigInteger.valueOf(0);
			return ans;
		}
		for(int i=k+1;i<=n;i++) ans = ans.multiply(BigInteger.valueOf(i));
		for(int i=1;i<=n-k;i++) ans = ans.divide(BigInteger.valueOf(i));
		if (ans.equals(BigInteger.valueOf(0))) ans = BigInteger.valueOf(1); return ans;
	}
	public static void main(String args[]){
		Scanner in = new Scanner(System.in);
	        int n = in.nextInt();
	        int m = in.nextInt();
	        int t = in.nextInt();

	        BigInteger ans = BigInteger.valueOf(0);
	        for(int i=1;i<=m;i++){
	        	if (t-i>=4) ans = ans.add(c(m,i).multiply(c(n,t-i)));
	        }
	        System.out.print(ans);
	}
}                               