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.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try(Scanner input = new Scanner(System.in)){
			long pascalTriangle[][] = new long[31][31];
			for(int i = 0; i < 31; i++) {
				for(int j = 0; j <=i;j++) {
					if(j==0||j==i) {
						pascalTriangle[i][j] = 1;
					}else {
						pascalTriangle[i][j] = pascalTriangle[i-1][j-1]+pascalTriangle[i-1][j];
					}
				}
			}
			
			String[] nmt =input.nextLine().split(" ");
			int n = Integer.parseInt(nmt[0]);
			int m = Integer.parseInt(nmt[1]);
			int t = Integer.parseInt(nmt[2]);

			System.out.println(calculate(n,m,t, pascalTriangle));
		}
    }

	private static long calculate(int n, int m, int t, long[][] pascalTriangle) {
		int numOfBoys = 0;
		int numOfGirls = 0;
		if(n>=t) {
			numOfBoys = t-1;
			numOfGirls = 1;
		}else {
			numOfBoys = n;
			numOfGirls = t-n;
		}
		long result = 0;

		while(numOfBoys>=4 && numOfGirls<=m) {
			result += pascalTriangle[n][numOfBoys]*pascalTriangle[m][numOfGirls];
			numOfBoys--;
			numOfGirls++;
		}
		return result;
		
	}
}
    	 		    		 	 	 	 		 	 		  	