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
/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Codechef1
{
    public static long c(long n, long k) {
        if (k > n) return 0;
        long res = 1;
        for (long i = n; i > k; i--) {
            res *= i;
            res /= (n - i + 1);
        }
        return res;
    }
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
	Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    long m = sc.nextLong();
    long t =sc.nextLong();
    int s = (int)m+(int)n;
    long ans=0;
        for (int i = 4; i < t; i++) {
            ans += c(n, i) * c(m, t - i);
        }
        System.out.println(ans);
    }
		
	}

