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 P131C
{

	/**
	 * @param args
	 */
	public static void main(String[] args)
	{
		// TODO Auto-generated method stub
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		int m = in.nextInt();
		int t = in.nextInt();
		long[][] pascalFactors = new long[m+n+1][m+n+1];
		for (int i=0; i<=m+n; i++)
			pascalFactors[i][0] = pascalFactors[i][i] = 1;
		
		for (int i=2; i<=m+n; i++)
			for (int j=1; j<i; j++)
				pascalFactors[i][j] = pascalFactors[i-1][j-1] + pascalFactors[i-1][j];
		long answer = 0;
		for (int i=0; i<=t-5; i++)
		{
			answer += pascalFactors[n][4+i] * pascalFactors[m][t-4-i];
		}
		System.out.println(answer);
		
	}
//	public static long combinication (int y, int x)
//	{
//		int a = Math.max(x-y, y);
//		int b = Math.min(x-y, y);
//		long answer = 1;
//		for (int i= a+1; i<=x; i++)
//			answer *= i;
//		for (int i = 2; i <= b; i++)
//			answer /= i;
//		return answer;
//	}

}
