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.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.*;

public class TestClass {
    public static void main(String args[] ) throws Exception {
 BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   String s[]=br.readLine().trim().split(" ");
          int n=Integer.parseInt(s[0]);
          int m=Integer.parseInt(s[1]);
          int t=Integer.parseInt(s[2]);
          long ans=0;
          for(int i=4;i<=t-1;i++){
              ans+=nCr(n,i)*nCr(m,t-i);
          }
          System.out.println(ans);
}
static long nCr(int n,int r){
    if(n==r)
    return 1;
    if(r==1 || n-r==1)
    return n;
    long result=1;
    for(int i=0;i<r;i++)
    {   
        result*=(n-i);
        result/=(i+1);
    }
    return result;
}
}