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.InputStream;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;


public class Main {

    static long memo[][] = new long[31][31];
    
    static long C(int n, int k)
    {
        if(k == 0)
            return 1;
        if(memo[n][k] != -1)
            return memo[n][k];
        if(n - k < k)
            return memo[n][k] = C(n, n - k);
        return memo[n][k] = n * C (n - 1, k - 1) / k;
    }
    public static void main(String[] args) throws IOException {
        
        for(int i = 0; i <= 30; i++)
            Arrays.fill(memo[i], -1);
    
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(), m = sc.nextInt(), t = sc.nextInt();
        long ans = 0;
        for(int i = Math.max(t - 4 - m, 0); i + 4 <= n && i <= t - 5; i++)
            ans += C(n, i + 4) * C(m, t - i - 4);
        
        System.out.println(ans);
    }
    
    static class Scanner 
    {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s){  br = new BufferedReader(new InputStreamReader(s));}

        public String next() throws IOException 
        {
            while (st == null || !st.hasMoreTokens()) 
                st = new StringTokenizer(br.readLine());
            return st.nextToken();
        }

        public int nextInt() throws IOException {return Integer.parseInt(next());}
        
        public long nextLong() throws IOException {return Long.parseLong(next());}

        public String nextLine() throws IOException {return br.readLine();}
        
        public double nextDouble() throws IOException
        {
            String x = next();
            StringBuilder sb = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-')
            {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++)
                if(x.charAt(i) == '.')
                {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                }
                else
                {
                    sb.append(x.charAt(i));
                    if(dec)
                        f *= 10;
                }
            res += Long.parseLong(sb.toString()) / f;
            return res * (neg?-1:1);
        }
        
        public boolean ready() throws IOException {return br.ready();}


    }
}
