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.BigDecimal;
import java.util.*;
import java.util.function.Function;

public class C {
    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        long n=fs.nextInt();
        long m=fs.nextInt();
        long t=fs.nextInt();
        if (t<5||n<4||m<1||n+m<t) {
            System.out.println(0);
            return;
        }
        int tt=4;
        for (tt=4;tt<t;tt++) {
            if (t-tt<=m) break;
        }
        BigDecimal boys=c(tt,n);
        BigDecimal girls=c(t-tt,m);
        BigDecimal result=boys.multiply(girls);
        for (long i=tt+1;i<t;i++) {
            boys=boys.multiply(BigDecimal.valueOf(n-i+1));
            boys=boys.divide(BigDecimal.valueOf(i));
            girls=girls.multiply(BigDecimal.valueOf(t-i+1));
            girls=girls.divide(BigDecimal.valueOf(m-t+i));
            result=result.add(boys.multiply(girls));
        }
        System.out.println(result.longValue());
    }

    private static BigDecimal c(long k, long n) {
        BigDecimal r = BigDecimal.ONE;
        for (long i=n;i>n-k;i--) {
            r=r.multiply(BigDecimal.valueOf(i));
        }
        for (long i=1;i<=k;i++) {
            r=r.divide(BigDecimal.valueOf(i));
        }
        return r;
    }

    public static class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
}
