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.io.*;

public class worldtheater{
    public static void main (String [] args) throws FileNotFoundException {
        Scanner in = new Scanner(System.in);//Scanner(System.in); //Scanner(new File("input.txt"));//
        // System.out.println(in.next());
        int n = in.nextInt();
        int m = in.nextInt();
        int t = in.nextInt();

        int total = n + m + 1;
        long[][] dp = new long[total][total];

        //Array.fill(total[])
        dp[0][0] = -1;
        dp[1][1] = -1;
        dp[1][0] = -1;
        for (int i = 2; i < total; i++) {
            for (int j = 1; j <= i; j++) {
                dp[i][0] = -1;
                dp[i][i] = -1;
                // if (i>1) 
                    dp[i][j] = dp[i-1][j-1] + dp[i-1][j];
                // System.out.println(dp[i][j+1]);
            }
            
        }
        long teams = 0;
        for (int i = 0; i <= t-5; i++) {
            teams += dp[n][4+i] * dp[m][t-4-i];
        }

        System.out.println(teams);
    }
}