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 TheWorldIsATheatre {
	
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		
		String[] info = br.readLine().split(" ");
		long n = Integer.parseInt(info[0]);
		long m = Integer.parseInt(info[1]);
		long t = Integer.parseInt(info[2]);
		
		BigInteger ans = BigInteger.ZERO;
		
		for (long i = 4; i <= Math.min(n, t-1); i++) {
			BigInteger hombres = comb(n,i);
			BigInteger mujeres = comb(m,t-i);
			ans = ans.add(hombres.multiply(mujeres));
		}
		
		System.out.println(ans);

	}
	
	static BigInteger comb(long n, long r) {
		BigInteger res = BigInteger.ONE;
		for (long i = 2; i <= n ; i++) {
			res = res.multiply(new BigInteger(i+""));
		}
		for (long i = 2; i <= r ; i++) {
			res = res.divide(new BigInteger(i+""));
		}
		for (long i = 2; i <= n-r ; i++) {
			res = res.divide(new BigInteger(i+""));
		}
		
		
		return res;
		
	}



}
