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.Scanner;

public class Main {
    
    int n , m  , k ;
    int i , j;
    long c[][] = new long[31][31];
    public void run(){
        Scanner sc = new Scanner(System.in);
        
        n = sc.nextInt();
        m = sc.nextInt();
        k = sc.nextInt();
        
        long ans = 0;
        
        for(i = 0 ; i<=Math.max(n, m) ; i++){
            c[i][0] = 1;
        
            for(j=1 ; j<=i ; j++){
                c[i][j] = c[i-1][j] + c[i-1][j-1];
            
            //System.out.println(i+" " + j + " =  " + c[i][j]);
            }
            
        }
        
        
        for(i = 4 ; i<k  ; i++){
            if( i<=n && (k-i)<=m)
            ans += c[n][i]*c[m][k-i];
        }
        
        System.out.println(ans);
        
    }

    public static void main(String[] args) {
        new Main().run();
    }
}
