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.*;
import java.math.*;

import static java.lang.System.*;

public class Solution131c {

    public void run() throws Exception {
        Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        long m = in.nextLong();
        long t = in.nextLong();
        long total = 0;
        for(int b = 4; b <= t - 1; b++) {
//            out.println(n + " " + b + " " + c(n,b));
//            out.println(m + " " + (t-b) + " " + c(m, t-b));
            total += c(n, b) * c(m, t - b);
        }
        out.println(total);
    }

    public long c(long i, long j) {
        long r = 1;
        for(long x = 0; x < j; x++) {
            r *= i - x;
            r /= x + 1;
        }
        return r;
    }

    public long f(long i, long j) {
        long x = 1;
        for(long r = i; r <= j; ++r)
            x *= r;
        return x;
    }

    public static void main(String[] args) throws Exception {
        new Solution131c().run();
    }
}
