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;
import java.util.StringTokenizer;


public class TheWorldIsATheatre {


    static BigInteger[] factorial = new BigInteger[101];
    
    public static void main(String[] args) throws IOException {
        factorial[0] = new BigInteger("1");
        for (int i = 1 ; i <= 100 ; i++) {
            factorial[i] = new BigInteger(i + "");
            factorial[i] = factorial[i].multiply(factorial[i-1]);
        }
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        int n = Integer.parseInt(st.nextToken());
        int m = Integer.parseInt(st.nextToken());
        int t = Integer.parseInt(st.nextToken());
        BigInteger ans = factorial[n + m].divide(factorial[t].multiply(factorial[n + m - t]));
        BigInteger nn = new BigInteger(n + "");
//      System.out.println(ans);
        if(m >= t - 1)
            ans = ans.subtract(nn.multiply(factorial[m].divide(factorial[t - 1].multiply(factorial[m - (t - 1)]))));
        if(m >= t - 2) {
            BigInteger temp = factorial[m].divide(factorial[t - 2].multiply(factorial[m - (t - 2)]));
            BigInteger temp2 = factorial[n].divide(factorial[2].multiply(factorial[n - 2]));
            ans = ans.subtract(temp.multiply(temp2));
        }
        if(m >= t - 3) {
            BigInteger temp = factorial[m].divide(factorial[t - 3].multiply(factorial[m - (t - 3)]));
            BigInteger temp2 = factorial[n].divide(factorial[3].multiply(factorial[n - 3]));
            ans = ans.subtract(temp.multiply(temp2));
        }
        if(n >= t)
            ans = ans.subtract(factorial[n].divide(factorial[t].multiply(factorial[n - t])));
        if(m >= t)
            ans = ans.subtract(factorial[m].divide(factorial[t].multiply(factorial[m - t])));
        System.out.println(ans);
    }

}
