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.*;
import java.math.*;
public class Main{
        static long C(int down, int up){
                if(up > down / 2){
                        up = down - up;
                }
                BigInteger res = BigInteger.ONE;
                for(int i = down; i > down - up; i--){
                        res = res.multiply(new BigInteger(Integer.toString(i)));
                }
                for(int i = up; i > 1; i--){
                        res = res.divide(new BigInteger(Integer.toString(i)));
                }
                return res.longValue();
        }
        
        public static void main(String[] args) throws Exception{
                Scanner scan = new Scanner(System.in);
                int n = scan.nextInt();
                int m = scan.nextInt();
                int t = scan.nextInt();
                int min = Math.max(4, t - m);
                int max = Math.min(n, t - 1);
                long res = 0;
                for(int i = min; i <= max; i++){
                        res += 1L * C(n, i) * C(m, t - i);
                }
                System.out.println(res);
                
        }
}