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.util.StringTokenizer;


public class WorldIsATheatre
{

    public static void main(String[] args) 
    {
        MyScanner sc = new MyScanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        int t = sc.nextInt();
        
        long ways = 0; /* hehe */
        for(int i = 1; i <= t - 4; i++)
        {
            ways += binomial(m,i)*binomial(n,t-i);
            
            
        }
        
        System.out.println(ways);
        
        
    }
    
    
    
    public static long binomial(int N, int K)
    {
    long[][] binomial = new long[N+1][K+1];

        // base cases
        for (int k = 1; k <= K; k++) binomial[0][k] = 0;
        for (int n = 0; n <= N; n++) binomial[n][0] = 1;

        // bottom-up dynamic programming
        for (int n = 1; n <= N; n++)
            for (int k = 1; k <= K; k++)
                binomial[n][k] = binomial[n-1][k-1] + binomial[n-1][k];

        return binomial[N][K];
    
    
    }
    
     public static 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;
      }

   }  
}