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.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main4 {
    
    static class Main {
        
        public Scanner sc;
        
        public void run() {
            long[][] dp = new long[61][61];
            for (int i = 0; i <= 60; i++)
                for (int j = 0; j <= 60; j++) {
                    if (j == 0) dp[i][0] = 1;
                    else if (i == j) dp[i][j] = 1;
                    else if (i > j) dp[i][j] = dp[i-1][j-1] + dp[i-1][j];
                    else dp[i][j] = 0;
                }
            int n = sc.nextInt(), m = sc.nextInt(), t = sc.nextInt();
            long ans = dp[n+m][t];
            ans -= dp[n][t];
            for (int i = 0; i <= 3; i++)
                ans -= dp[n][i] * dp[m][t-i];
            System.out.println(ans);
        }
        
    }
    
    public static void main(String[] args) {
        Main main = new Main();
        try { main.sc = new Scanner(new FileInputStream("test.in")); }
        catch (FileNotFoundException e) { main.sc = new Scanner(System.in); }
        main.run();
    }
    
}
