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 Main {
    
    public static long comb(int n, int K) {
        long nCk = 1;
        for (int k = 0; k < K; k++) {
            nCk = (long)nCk * (n-k) / (k+1);
        }
        return nCk;
    }
    
    public static long solve(int n, int m, int t) {
        long r = 0;
        for(int i = 4; i < t; i++) {
            if(i > n || t - i > m) continue;
            r += comb(n, i) * comb(m, t - i);
        }
        return r;
    }
    
    public static void main(String [] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(), m = sc.nextInt(), t = sc.nextInt();
        System.out.println(solve(n, m, t));
    }
}
