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 Test {
    static Scanner input = new Scanner(System.in);
    static long calcCompin(int n,int k)
    {
        double uNumerator =1,denominator=1 ;
        for (int i = n; i > (n-k); i--) //n...n-k+1
            uNumerator*=i;
        for (int i = k; i > 0; i--) 
            denominator*=i;
        return  Math.round(uNumerator/denominator);
    }
    public static void main(String[] args) {
        int n = input.nextInt(),m= input.nextInt(),t= input.nextInt();
        int i=(t>n)?n:t-1 ;
        int j=(t>n)?t-n:1 ;
        long total = 0 ;
        while (i+j==t&&i>=4&&i<=n&&j<=m&&j>=1)//i from 4 to n ---- j from 1 to m ---- i+j=t
        {
            long sum=(long)calcCompin(n,i);
            sum*=calcCompin(m,j);
            total+=sum;
            i--;
            j++;  
        }
        
        System.out.println((long)total);
    }  
}