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 javax.management.RuntimeErrorException;

public class Main implements Runnable {
	private BufferedReader in;
	private PrintWriter out;
	private StringTokenizer st;
	private Random rnd;
	
	private BigInteger factorial(long n) {
		BigInteger res = BigInteger.ONE;
		for(long i = 2; i <= n; i++) res = res.multiply(BigInteger.valueOf(i));
		return res;
	}
	
	private BigInteger C(long n, long k) {
		BigInteger res = factorial(n).divide(factorial(n - k)).divide(factorial(k));
		return res;
	}
	
	private void solve() throws IOException {
		long mans = nextLong(), girls = nextLong(), total = nextLong();
		
		long remain_mans = mans - 4;
		long remain_girls = girls - 1;
		
		BigInteger res = BigInteger.ZERO;
		
		for(long cur_mans = 0; cur_mans <= remain_mans; cur_mans++) {
			for(long cur_girls = 0; cur_girls <= remain_girls; cur_girls++) {
				long cur_total = 4 + 1 + cur_mans + cur_girls;
				
				if(cur_total != total) continue;
				
				long mans_now = cur_mans + 4;
				long girls_now = cur_girls + 1;
				
				res = res.add(C(mans, mans_now).multiply(C(girls, girls_now)));
				
				//out.println(cur_mans + " " + cur_girls);
			}
		}
		
		out.println(res);
	}
		
	public static void main(String[] args) {
		new Main().run();
	} 
	
	public void run() {
		try {
			try {
				in = new BufferedReader(new FileReader("javanese.in"));
				out = new PrintWriter(new FileWriter("javanese.out"));
			} catch(FileNotFoundException e) {
				in = new BufferedReader(new InputStreamReader((System.in)));
				out = new PrintWriter(System.out);	
			}
			
			st = null;
			rnd = new Random();
			
			solve();
			
			out.close();
		} catch(IOException e) {
			e.printStackTrace();
		}	
	}
	
	private String nextToken() throws IOException, NullPointerException {
		while(st == null || !st.hasMoreTokens()) {
			st = new StringTokenizer(in.readLine());
		}
		
		return st.nextToken();
	}
	
	private int nextInt() throws IOException {
		return Integer.parseInt(nextToken());
	}
	
	private long nextLong() throws IOException {
		return Long.parseLong(nextToken());
	}
	
	private double nextDouble() throws IOException {
		return Double.parseDouble(nextToken());
	}

}