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.math.BigInteger;
import java.util.Scanner;

public class theaterchoice {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		long m = scan.nextLong();
		long t = scan.nextLong();
		
		long tot = 0;
		
		for(int i = 4; i <= n; i++){
			long g = t-i;
			if(g > m || g <= 0) {
				continue;
			} else {
				tot += choose(n,i).longValue()*choose(m,g).longValue();
			}
		}
		
		System.out.println(tot);
	}
	
	/*public static long choose(long total, long choose){
	    if(total < choose)
	        return 0;
	    if(choose == 0 || choose == total)
	        return 1;
	    return choose(total-1,choose-1)+choose(total-1,choose);
	}*/
	
	public static BigInteger choose(long x, long y) {
	    if (y < 0 || y > x) return BigInteger.ZERO;
	    if (y == 0 || y == x) return BigInteger.ONE;

	    BigInteger answer = BigInteger.ONE;
	    for (long i = x - y + 1; i <= x; i++) {
	        answer = answer.multiply(BigInteger.valueOf(i));
	    }
	    for (long j = 1; j <= y; j++) {
	        answer = answer.divide(BigInteger.valueOf(j));
	    }
	    return answer;
	}
}
