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 P131C {
    public static void main(String[] args)
    {
        Scanner in = new Scanner(System.in);
        
        // populate pascal's triangle
        long[][] choose = new long[61][61];
        choose[0][0] = 1;
        choose[1][0] = 1;
        choose[1][1] = 1;
        for (int i = 2; i < 61; ++i)
        {
            for (int j = 0; j <= i; ++j)
            {
                choose[i][j] = choose[i-1][j];
                if (j-1 >= 0)
                    choose[i][j] += choose[i-1][j-1];
                //System.out.print(choose[i][j] + " " );
            }
            //System.out.println();
        }
        
        int N = in.nextInt();
        int M = in.nextInt();
        
        int T = in.nextInt();
        
        long ans = choose[N+M][T];
        
        // Minus ways to pick all boys
        if (T <= N)
            ans -= choose[N][T];
        
        // Minus ways to pick 3 or less boys
        if (T <= M)
            ans -= choose[M][T];
        if (T-1 <= M)
            ans -= choose[M][T-1]*choose[N][1];
        if (T-2 <= M && N >= 2)
            ans -= choose[M][T-2]*choose[N][2];
        if (T-3 <= M && N >= 3)
            ans -= choose[M][T-3]*choose[N][3];
        
        System.out.println(ans);
    }
}
