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.*;
public class c22{
	public static void main(String[] args)
	{
		Scanner scn= new Scanner(System.in);
		int n,m,t;
		n=scn.nextInt();
		m=scn.nextInt();
		t=scn.nextInt();
		long prod[][]= new long[31][31];
		// prod[0]=1;
		long factn=1,factm=1,ans=0;
		int i=1;
		/*while(i<=n)
		{
			factn*=i++;
		}
		i=1;
		while(i<=n)
		{
			factm*=i++;
		}*/
		i=0;
		prod[1][0]=1;
		while(i<31)
		{
			prod[i][0]=1;
			int p=1;
			while(p<=i)
			{
				prod[i][p]=(prod[i][p-1]*(i-p+1))/(p);
				p++;
			}
			i++;
		}


		// for(int h=1;h<5;h++)
		// {
		// 	for( int d=0;d<31;d++)
		// 	{
		// 		System.out.print(prod[h][d]+" ");
		// 	}
		// 	System.out.println();
		// }
		int j=4;

		while(j<=n&&j<t)
		{
			if(t-j<=m)
			{
				ans+=prod[n][j]*prod[m][t-j];
			}
			j++;
		}
		System.out.println(ans);
	}

}