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 A{
    public static void main(String arg[]){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(), m = sc.nextInt(), t = sc.nextInt();
        long ans = 0;
        // long fact[] = new long[31];
        // fact[0] = 1;
        // for(int i=1;i<=30;i++) fact[i] = i*fact[i-1];
        // System.out.println(fact[20]);
        for(int i=4;i<=t-1;i++){
            if(i<=n && (t-i)<=m)
                ans += fun(n, i)*fun(m, t-i);
        }
        System.out.println(ans);
    }
    static long fun(int n, int r){
        int d1 = Math.max(r, n-r), d2 = n - d1;
        long ans = 1;
        long j = 1;
        for(long i=d1+1;i<=n;i++){
            ans = ans*i;
            if(ans%j==0 && j<=d2){
                ans = ans/j;
                j++;
            }
        }
        while(j<=d2){
            ans = ans/j;
            j++;
        }
        return ans;
    }
}