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.ArrayList;
import java.util.List;
import java.util.Scanner;

public class TheWorldIsATheatre {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String[] nmt = scanner.nextLine().split(" ");
        int n = Integer.parseInt(nmt[0]), m = Integer.parseInt(nmt[1]),
                t = Integer.parseInt(nmt[2]);
        List<int[]> pairs = new ArrayList<>();
        for (int i = 1; i <= m; i++) {
            int boy = t - i;
            if (boy >= 4 && boy <= n) {
                pairs.add(new int[]{boy, i});
            }
        }
        long[][] pascalTriangle = new long[32][32];
        long total = 0;
        for (int[] pair : pairs) {
            total += (pascalTriangle(n, pair[0], pascalTriangle) *
                    pascalTriangle(m, pair[1], pascalTriangle));
        }

        System.out.println(total);
    }

    private static long pascalTriangle(int row, int col, long[][] tri) {
        if (col == 0 || row == col) {
            return 1;
        } else {
            if (tri[row][col] == 0) {
                tri[row][col] = pascalTriangle(row - 1, col, tri) +
                        pascalTriangle(row - 1, col - 1, tri);
            }
            return tri[row][col];
        }
    }
}
