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 {
    static final Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        final int MAX = 100;
        long[][] comb = new long[MAX][MAX];
        for(int i = 0; i < MAX; i++) {
            comb[i][0] = comb[i][i] = 1;
            for(int j = 1; j < i; j++)
                comb[i][j] = comb[i-1][j-1] + comb[i-1][j];
        }

        final int n = sc.nextInt();
        final int m = sc.nextInt();
        final int t = sc.nextInt();
        
        long res = 0;
        for(int i = 4; i <= n; i++) {
            if(t-i >= 1) {
                res += comb[n][i] * comb[m][t-i];
            }
        }
        System.out.println(res);
    }
}
