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.*;
 
public class TheWorldIsATheatre{
 
   public static void main(String args[]) throws IOException {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
      StringTokenizer st = new StringTokenizer(br.readLine());
      int b = Integer.parseInt(st.nextToken());
      int g = Integer.parseInt(st.nextToken());
      int t = Integer.parseInt(st.nextToken());
      
      int gC = 1;
      long sum = 0;
      while(gC <= g){
         int bC = t-gC;
         if(bC >= 4 && bC <= b){
            sum += c(g,gC)*c(b,bC); 
         }
         gC++;
      }      
      bw.write(sum + "" +'\n');
      bw.flush();
      br.close();
      bw.close();
   }
   
   public static long c(int n, int k){
      long ans = 1;
      
      for(int i = 1; i <= k; i++){
         ans *= (n-i+1);
         ans /= i;
      }
      
      return ans;
   }
}