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 FFirst {
    public static void main (String [] args) {
        int N = 77;
        long [][] dp = new long [N][N];
        for (int i = 1; i < N; i++) {
            dp[i][1] = i;
            dp[i][i] = 1;
            dp[i][0] = 1;
        }

        for (int i = 2; i < N; i++) {
            for (int j = 2; j <= i; j++) {
                dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
            }
        }
        Scanner cin = new Scanner(System.in);
        int n = cin.nextInt();
        int m = cin.nextInt();
        int t = cin.nextInt();
        int x = 4;
        long sum = 0;
        while (t - x > 0) {
            long first = dp[n][x] * dp[m][t - x];
            sum += first;
            x++;
        }
        System.out.print(sum);
    }
}