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.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;

public class The_World_is_a_Theatre2 { //combinatorics.

    static long [][] dp;
    
    static long C(int n, int r){
        if(r==0) return 1;
        if(n==0) return 0;
        if(dp[n][r]!=-1) return dp[n][r];
        return dp[n][r] = C(n-1, r-1) + C(n-1, r);
    }
    
    /**
     * @param args
     */
    public static void main(String[] args) throws  Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());

        int boys = Integer.parseInt(st.nextToken());
        int girls = Integer.parseInt(st.nextToken());
        int needed = Integer.parseInt(st.nextToken());
        dp = new long[Math.max(boys,girls)+1][needed+1];
        
        for (int i = 0; i < dp.length; i++) {
            Arrays.fill(dp[i], -1);
        }
        
        long ways = 0;
        for (int i = 4; i <= boys; i++) {
            if(needed-i >= 1){
                ways += C(boys, i) * C(girls, needed-i);
            }
        }
        
        System.out.println(ways);
    }
}