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 {
    public static void main(String[] args) {
        long[][] c = new long[70][70];
        
        c[0][0] = 1;
        for(int n = 1; n < 70; n++)
        for(int r = 0; r < 70; r++)
            c[n][r] = (r-1>=0?c[n-1][r-1]:0) + c[n-1][r];
        
//      System.out.println(c[4][2]);
        
        Scanner r = new Scanner(System.in);
        while(r.hasNext()){
            int n = r.nextInt();
            int m = r.nextInt();
            int t = r.nextInt();
            
            long ways = 0;
            
            for(int g = 1; g <= m; g++){
                for(int b = 4; b <= n; b++){
                    if(b + g == t){
                        ways += c[n][b] * c[m][g];
                    }
                }
            }
            
            System.out.println(ways);
        }
    }
}
