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.PrintWriter;
import java.util.Scanner;

public class C {
	static Scanner in; static int next() throws Exception {return in.nextInt();};
//	static StreamTokenizer in; static int next() throws Exception {in.nextToken(); return (int) in.nval;}
//	static BufferedReader in;
	static PrintWriter out;


	public static void main(String[] args) throws Exception {
        in = new Scanner(System.in);
//		in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
//		in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);

        long a[][] = new long[33][33];
        for (int i = 0;i < 33;i++) {
            a[i][1] = 1;
            a[i][i] = 1;
        }
        for (int i = 0;i < 33;i++) {
            a[i][0] = 0;
            a[0][i] = 0;
        }
        for (int i = 2;i < 33;i++) {
            for (int j = 2;j < i;j++) a[i][j] = a[i-1][j] + a[i-1][j-1];
        }


        int n = next(), m = next(), t = next();

        long res = 0;
        for (int i = 1;i <= t-4;i++) {
            if (i <= m && t-i <= n) res += a[m+1][i+1]*a[n+1][t-i+1];
        }
        out.println(res);


        out.println();
		out.close();
	}
}