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.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.util.Vector;

public class Main {

	static long gcd(long a, long b) {
		if (b == 0)
			return a;

		return gcd(b, a % b);

	}
	
	
	
	static long C(int n,int m )
	
	{
		long z = 1;
		
		for(int i=0;i<m;i++)
		z=z*(n-i)/(i+1);
		
		
		return z;
		
	}
	

	public static void main(String[] args) throws IOException {
		FastReader in = new FastReader();

		int n =in.nextInt(),m=in.nextInt(),t=in.nextInt();

	System.out.println(C(n+m,t)-C(n,t)-C(m,t)-C(n,1)*C(m,t-1)-C(n,2)*C(m,t-2)-C(n,3)*C(m,t-3));
	
	
	
	
	
	
	
	}}

class FastReader {
	BufferedReader br;
	StringTokenizer st;

	public FastReader() {
		br = new BufferedReader(new InputStreamReader(System.in));

	}

	String next() {
		while (st == null || !st.hasMoreElements()) {
			try {
				st = new StringTokenizer(br.readLine());

			} catch (IOException e) {
				e.printStackTrace();
			}

		}

		return st.nextToken();

	}

	int nextInt() {

		return Integer.parseInt(next());
	}

	double nextDouble() {

		return Double.parseDouble(next());
	}

	long nextLong() {

		return Long.parseLong(next());
	}

	String nextLine() {
		String str = "";
		try {
			str = br.readLine();

		} catch (IOException e) {

			e.printStackTrace();
		}
		return str;

	}

}
