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.lang.StringBuilder;

public class Solution131C {


    public static long C(int n, int m) {
        long res = 1;

        for (int i = 0 ; i < m ; i++) {
            res *= (n - i);
            res /= (i + 1);
        }

        return res;
    }


	public static void main(String[] args) {

		//Scanner sc = new Scanner(System.in);
		MyScanner sc = new MyScanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        int t = sc.nextInt();

        long result = 0;
        for (int i = 4 ; i <= t-1 ; i++) {
            result += C(n, i) * C(m, t-i);
        }

        System.out.println(result);
	}
}



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;
 	}
}