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.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;


public class M8CFTheWorldisaTheatre {
    public static long combinations(int n,int r){
        long ans=1;
        r=Math.min(r, n-r);
        for (int i=1;i<r+1;i++){
            ans=ans*(n-r+i);
            ans=ans/i;
        }
        
        return ans;
        
    }
    
public static void main(String[] args)throws IOException {
    BufferedReader bf=new BufferedReader(new InputStreamReader(System.in));
    String input=bf.readLine();
    String in[]=input.split(" ");
    int n=Integer.parseInt(in[0]);
    int m=Integer.parseInt(in[1]);
    int t=Integer.parseInt(in[2]);
    long allcases=combinations(n+m,t);
    long noGirls=0;
    if (n>=t)
    noGirls=combinations(n, t);
    long subtract=0;
    
    for (int i=3;i>=0;i--){
        if (t-i<=m)subtract+=combinations(m, t-i)*combinations(n, i);
        else break;
        
    }

    System.out.println(allcases-subtract-noGirls);
    
}
}
