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
/*
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 * and open the template in the editor.
 */



import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 *
 * @author sousnake
 */
public class dp2 {
    public static void main(String args[]) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String s[]  = br.readLine().split(" ");
         int N = Integer.parseInt(s[0]);
         int M =  Integer.parseInt(s[1]);
         int T =  Integer.parseInt(s[2]);
         if(T==5){
             System.out.println(cr(N,4)*cr(M,1));
             return;
         }
         else{
             int i=4;
             long ans=0;
             while(i<=N&&(T-i)>=1){
                 ans+= cr(N,i)*cr(M,T-i);
                 i++;
             }
             System.out.println(ans);
         }
        // System.out.println(cr(N,4)*cr(M,1)*cr(N+M-5,T-5));
         
         
    }
    public static long cr(long a,long b){
        if(b==0)
            return 1;
        else return a*cr(a-1,b-1)/b;
        
    }
}
