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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

public class ProblemC {


    public static void main(String[] args) throws IOException {
        BufferedReader s = new BufferedReader(new InputStreamReader(System.in));
        String line = s.readLine();
        String[] data = line.split(" ");
        int n = Integer.valueOf(data[0]);
        int m = Integer.valueOf(data[1]);
        int t = Integer.valueOf(data[2]);

        long[][] c = new long[31][31];
        c[0][0] = 1;
        for (int r = 1 ; r <= 30 ; r++) {
            c[r][0] = 1;
            c[r][r] = 1;
            for (int rr = 1 ; rr < r ; rr++) {
                c[r][rr] = c[r-1][rr-1] + c[r-1][rr];
            }
        }
        
        long answer = 0;
        for (int man = 4 ; man <= t - 1 ; man++) {
            if (man <= n && (t - man) <= m) {
                answer += c[n][man] * c[m][t - man];
            }
        }
        
        System.out.println(answer);
    }
}