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.util.*;	
import java.io.*;

public class Main {
	
	static long[][] dp;
	
	public static void main (String[]args) throws IOException{
		
		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 n = Integer.parseInt(st.nextToken());
		int size = n+boys+girls;
		dp = new long[size][size];
		for(int i=1; i<size; i++) Arrays.fill(dp[i],-1);
		
		long sum = 0;
		
		for(int i=4; i<=n-1; i++){
			sum+= recur(boys, i) * recur(girls, n-i);
			//System.out.println(recur(boys,i) + " " + recur(girls, n-i));
		}
		System.out.println(sum);
	}
	
	public static long recur(int n, int k){
		if(k>n) return 0;
		if(k==n || k==0) return 1;
		if(dp[n][k]!=-1) return dp[n][k];
		return dp[n][k] = recur(n-1, k) + recur(n-1,k-1);
	}
}
