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 hellolinux;

import java.util.Scanner;

public class HelloLinux {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int t = sc.nextInt();
        long[][] c = new long[61][61];
        for (int i = 0; i < 61; i++) {
            c[i][0] = 1;
            c[0][i] = 1;
        }
        for (int i = 1; i < 61; i++) {
            for (int j = 0; j < 61; j++) {
                c[i][j] = c[i - 1][j] * (j - i + 1) / i;
            }
        }
        int minboys = 4;
        int maxboys = t - 1;
        long result = 0;
        for (int boys = minboys; boys < maxboys + 1; boys++) {
            int girls = t - boys;
            if (boys < n + 1 && girls < m + 1) {
                result += c[boys][n] * c[girls][m];
            }
        }
        System.out.println(result);
    }
}