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.io.*;
import java.util.*;

public class C {
    static long binomialCoeff(int n, int k) {
        long res = 1;
        
        if (k > n - k) k = n - k;
        
        for (var i = 0; i < k; ++i) {
            res *= 1L*(n - i);
            res /= 1L*(i + 1);
        }
        
        return res;
    }

    public static void main(String[] args) {
        var in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        
        var n = in.nextInt();
        var m = in.nextInt();
        var t = in.nextInt();
        
        long ans = 0;
        for (var i = 4; i <= n; ++i)
            for (var j = 1; j <= m; ++j)
                if(i + j == t)
                    ans += binomialCoeff(n, i) * binomialCoeff(m, t - i);
        System.out.print(ans);
    }
}