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.math.BigDecimal;
import java.util.Scanner;

public class theWorldIsTheater {
    static BigDecimal fac2(int n) {
        if (n <= 1)
            return new BigDecimal(1);
        return new BigDecimal(n).multiply(fac2(n - 1));
    }

    static long c(int n, int r) {
        BigDecimal b = fac2(r).multiply(fac2(n - r));
        return fac2(n).divide(b).longValue();
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int t = sc.nextInt();
        int N = (t - 1 > n) ? n : t - 1;
        int M = t - N;
        long res = 0;
        while (N >= 4) {
            res += c(n, N) * c(m, M);
            N--;
            M++;
            if(M>m||N>n)break;
        }
        System.out.println(res);
    }
}
