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 a
{
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        int n = input.nextInt(), m = input.nextInt(), t = input.nextInt();
        long res = 0;
        long[][] comb = comb(61);
        for(int i = 4; i<= t - 1; i++)
            res += comb[n][i]*comb[m][t-i];
        System.out.println(res);
    }
    //Returns array of combinations (Pascals's triangle) up to nCn - O(n^2)
    //comb[i][j] represents the value of i choose j
    public static long[][] comb(int n)
    {
        long[][] comb = new long[n+1][n+1];
        for(int i = 0; i<= n; i++)
            comb[i][0] = 1;
        for(int i = 1; i<= n; i++)
            for(int j = 1; j<= i; j++)
                comb[i][j] = (comb[i-1][j] + comb[i-1][j-1]);
        return comb;
    }
}