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 C_131 {

    /**
     * @param args
     */
    public static void main(String[] args) throws Exception{
        // TODO Auto-generated method stub
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        int m=sc.nextInt();
        int t=sc.nextInt();
        
        
        long sum=0;
        int i= m+4 >= t ? 4 : t-m;
        for( ;i<=t-1 && i<=n;i++){
            sum+=Cnk(n, i)*Cnk(m, t-i);
        }
        
        System.out.println(sum);
    }
    
    private static long Cnk(long n, long k){
        long res=1;
        for(int i=1;i<=k;i++)
            res=(res*(n-k+i))/i;
            
        return res; 
    }
}
