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.*;
import java.util.HashSet;

import java.util.StringTokenizer;

public class C131{

    public static void main(String[] args) throws IOException {
       Scanner in  = new Scanner(System.in);
       int n = in.nextInt();
       int m = in.nextInt();
       int t = in.nextInt();
       int sum =n+m;
      long [][] dp =new long[t+1][t+1];
      dp[0][0]=1;
      
      for(int i =1; i<=n; ++i){
          for(int j =t; j>=1; --j){
              for(int k =1; k<t; ++k){
                  dp[j][k] +=dp[j-1][k-1]; 
              }
          }
          
      }

      
       for(int i =1; i<=m; ++i){
         for(int j=t; j>=1; --j){
              for(int k =1; k<t; ++k){
                  dp[j][k] +=dp[j-1][k]; 
                }

        }
      }
      
      long result =0;
      for(int i=4; i<=Math.min(t-1, n); ++i){
          result+=dp[t][i];
      }
      
      System.out.println(result);
 
    }

  
}