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.*;
import java.io.*;
import java.math.BigInteger;
public class Main {

   static BigInteger fac(int A)
   {
       if(A==0)return new BigInteger("1");
       BigInteger Fact = new BigInteger("1");
       for (int i = 1 ; i <= A ;i++)
       {
           Fact = Fact.multiply(new BigInteger(""+i));
       }
   return Fact;
  
   
   }
    
    
    
    public static void main(String[] args) throws IOException {
     BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
     long sum = 0;
     ArrayList<Long> Arr = new ArrayList<>();
    StringTokenizer input = new StringTokenizer(in.readLine());
    int n , m , t ;
    n = Integer.parseInt(input.nextToken());m=Integer.parseInt(input.nextToken());
    t=Integer.parseInt(input.nextToken());
    for (int i = 4 ; i <= n ; i++)
    {   sum  = 0;
        if(t-i==0)break;
        sum+=fac(n).divide((fac(i)).multiply(fac(n-i))).longValue();
        
      sum = sum * fac(m).divide((fac(t-i)).multiply(fac(m-(t-i)))).longValue();
       Arr.add(sum);
    }
        sum = 0;
        for (int i = 0 ; i <Arr.size();i++)
        {
            sum+=Arr.get(i);
        }
        System.out.println(sum);
    }
     
        
      }
    
    
