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.*;

public class Main {

    public static void main(String[] args) {
        Scanner kb = new Scanner(System.in);
        int n = kb.nextInt();
        int m = kb.nextInt();
        int t = kb.nextInt();
        int size = Math.max(n, m) + 1;
        long mem[][] = new long[size][size];
        long sum = 0;
        for (int i = 4; i <= t - 1; i++) {
            int boy = i;
            int girl = t - i;
            long temp = c(n, boy, mem) * c(m, girl, mem);
            sum += temp;
        }
        System.out.println(sum);
    }

    public static long c(int n, int r, long m[][]) {
        if (r == 0 || r == n)
            return 1;
        if (r < 0 || r > n)
            return 0;
        if (m[n][r] > 0)
            return m[n][r];
        return m[n][r] = c(n - 1, r, m) + c(n - 1, r - 1, m);
    }
}