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;

public class R95D2_C {
    static long comb[][];

    public static void comb(int n) {
        comb = new long[n][n];
        for (int i = 0; i < n; i++) {
            comb[i][0] = 1;
        }
        for (int i = 1; i < n; i++) {
            comb[i][i] = 1;
            for (int j = i - 1; j > 0; j--) {
                comb[i][j] = comb[i - 1][j - 1] + comb[i - 1][j];
            }
        }
    }

    public static void main(String[] args) throws NumberFormatException,
            IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

        String[] s = in.readLine().split(" ");
        // String s = in.readLine();
        int n = Integer.parseInt(s[0]);
        int m = Integer.parseInt(s[1]);
        int t = Integer.parseInt(s[2]);
        long res = 0;
        comb(32);
        for (int i = 4; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                if (i + j == t)
                    res += comb[n][i] * comb[m][j];
            }
        }
        System.out.println(res);
    }
}
