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.*;

public class cf131c {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		int m = in.nextInt();
		int t = in.nextInt();
		long[][] pasc = new long[100][100];
		for(int i=0; i<100; i++)
			for(int j=0; j<=i; j++)
				if(j==0) pasc[i][j] = 1;
				else pasc[i][j] = pasc[i-1][j] + pasc[i-1][j-1];
		long ans = 0;
		for(int boy = 4; boy < t; boy++) {
			int girl = t-boy;
			ans += pasc[n][boy]*pasc[m][girl];
		}
		System.out.println(ans);
	}
}
