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.Scanner;


public class C {
    public static void main(String[] args) {
        long com[][] = new long [31][31];
        for (int i = 0; i <com.length; i ++) {
            com[i][0] = 1;
            for (int j = 1; j <= i; j ++) {
                com[i][j] = 0;
                if (i > 0 && j > 0) com[i][j] += com[i-1][j-1];
                if (j > 0) com[i][j] += com[i-1][j];
                
            }
        }
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        int t = scanner.nextInt();
        long ans = 0;
        for (int i = 4; i <= n; i ++  ) {
            int j = t - i;
            if (j > 0 && j <= m) {
                ans += com[n][i] * com[m][j];
            }
        }
        System.out.println(ans);

    }

}
