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 Fhg {
    private static Scanner in=new Scanner(System.in);
    private static long boy,girl,tr,ans;
    public static void main(String[] args) {
        boy=in.nextInt();
        girl=in.nextInt();
        tr=in.nextInt();
        long gir,bo;
        for(int i=4;i<=boy;i++){
        for(int j=1;j<=girl;j++){
        if(i+j==tr){bo=coo(i,boy);
        gir=coo(j,girl);
        ans+=(bo*gir);
        break;}
        }
        }
        System.out.println(ans);
    }
    static long coo(int o,long u){
    return o==0?1:u*coo(o-1,u-1)/o;
    
    }}