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;
import java.io.PrintWriter;
import java.util.StringTokenizer;


public class TheWorldIsThethre {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		MyScanner input = new MyScanner();
		PrintWriter out = new PrintWriter(System.out);
		int n = input.nextInt();
		int m = input.nextInt();
		int t = input.nextInt();
		long total = ncr(n+m,t);
		if(t<=n)total-=ncr(n,t);
		if(t<=m)total-=ncr(m,t);
		if(t-1<=m)total-=(ncr(n,1)*ncr(m,t-1));
		if(t-2<=m)total-=(ncr(n,2)*ncr(m,t-2));
		if(t-3<=m)total-=(ncr(n,3)*ncr(m,t-3));
	
		System.out.println(total);
	}

	static class MyScanner {
		BufferedReader br;
		StringTokenizer st;
		public MyScanner() {
			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());}
		long nextLong() {return Long.parseLong(next());}
		double nextDouble() {return Double.parseDouble(next());}
		String nextLine(){String str = "";
		try {str = br.readLine();}
		catch (IOException e) {e.printStackTrace();}
		return str;}
	}
	
	static long ncr(int n, int r){
		double total=1;
		if(n-r<r)r = n-r; 
		
		for(int i=1; i<=r;i++){
			total = total*(n-r+i)/i;
		}
		return (long)(total +0.01);
		
		}
}
