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.*;

    public class Problem {

            public static void main(String[] args) {
                    Scanner in = new Scanner(System.in);
                    int B = in.nextInt();
                    int G = in.nextInt();
                    int t = in.nextInt();
                    long[][] pd = new long[61][61];
                    pd[0][0] = 1;
                    for(int i = 1; i <= 60; i++) {
                            pd[i][0] = pd[i-1][0];
                            for(int j = 1; j <= i; j++) {
                                    pd[i][j] = pd[i-1][j-1] + pd[i-1][j];
                            }
                    }
                    long count = 0;
                    for(int g = 1; g <= G; g++) {
                            int b = t-g;
                            if(b >= 4) count += pd[G][g]*pd[B][b];
                    }
                    System.out.println(count);
                    in.close();
            }
    }

