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.math.BigInteger;
import java.util.*;
public class TheWorldIsATheatre {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long b = in.nextLong();
        long g = in.nextLong();
        long t = in.nextLong();
        long g2 = 1;
        long b2;
        BigInteger sum = new BigInteger("0");
        while(true){
            b2 = t - g2;
            while(b2 > b){
                g2++;
                b2 = t - g2;
            }
            if(b2 >= 4 && g2 <= g){
               BigInteger x1 = new BigInteger("1");
               BigInteger x2 = new BigInteger("1");
                for (long i = 2; i <= b; i++) {
                    String st = ""+i;
                    x1 = x1.multiply(new BigInteger(st));
                    if(i <= b2)
                        x2 = x2.multiply(new BigInteger(st));
                }
                BigInteger y1 = new BigInteger("1");
                BigInteger y2 = new BigInteger("1");
                for (long i = 2; i <= g; i++) {
                    String st = ""+i;
                    y1 = y1.multiply(new BigInteger(st));
                    if(i <= g2)
                        y2 = y2.multiply(new BigInteger(st));
                }
                long db = b - b2;
                long dg = g - g2;
                BigInteger zb = new BigInteger("1");
                for (long i = 2; i <= db; i++) {
                    String st = ""+i;
                    zb = zb.multiply(new BigInteger(st));
                }
                BigInteger zg = new BigInteger("1");
                for (long i = 2; i <= dg; i++) {
                    String st = ""+i;
                    zg = zg.multiply(new BigInteger(st));
                }
                sum = sum.add((x1.divide(x2.multiply(zb))).multiply(y1.divide(y2.multiply(zg))));
                g2++;
            }
            else
                break;
        }
        System.out.println(sum);
    }
}
