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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class TheWorldisaTheatre {
	public static long comp(int n, int r) {
		long ans = 1;
		for (int i = 1; i <= r; i++) {
			ans = ans * (n - r + i) / i;
		}
		return ans;
	}

	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		String x[] = in.readLine().split(" ");
		int boy = Integer.parseInt(x[0]);
		int girl = Integer.parseInt(x[1]);
		int group = Integer.parseInt(x[2]);
		if (group > boy + girl)
			System.out.println(0);
		else {
			int b = 4;
			int g = group - 4;
			while(g>girl){
				g--;
				b++;
			}
			long answer = 0;
			for (int i = 0; i < 1000000; i++) {
				if (b > boy)
					break;
				else if (g<=0)
					break;
				long ans1 = comp(boy, Math.min(b, boy - b));
				long ans2 = comp(girl, Math.min(g, girl - g));
				answer+=(ans1*ans2);
				b++;
				g--;
			}
			System.out.println(answer);
		}
	}

}
