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) {
        try(Scanner sc = new Scanner(System.in)) {
            int n = sc.nextInt(), m = sc.nextInt(), t = sc.nextInt();
            long[][] C = computC(Math.max(n, m) + 1);
            long ans = 0l;
            for(int a = 4; a < t; a++) {
                if(a > n || t - a > m) {
                    continue;
                }
                ans+=C[n][a] * C[m][t - a];
            }
            System.out.println(ans);
        }
    }
    public static long[][] computC(int n) {
        long[][] C = new long[n][n];
        for(int i = 0; i < n; i++) {
            C[i][0] = C[i][i] = 1;
            for(int j = 1; j < i; j++) {
                C[i][j] = C[i - 1][j] + C[i - 1][j - 1];
            }
        }
        return C;
    }
}