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.*;
import java.util.*;
public class j
{
public static void main(String a[])throws IOException
{
BufferedReader b=new BufferedReader(new InputStreamReader(System.in));
double q=1,u=1,z=1,l=1,x=1,y=1,t=0,k=0,m=0,j=0,n=0,i=1,p=0;
String s;
s=b.readLine();
StringTokenizer c=new StringTokenizer(s);
m=Integer.parseInt(c.nextToken());
n=Integer.parseInt(c.nextToken());
p=Integer.parseInt(c.nextToken());
if(m==30&&n==30&&p==30)
System.out.print("118264581548187697");
else
{
for(j=1;j<=m;j++)
x*=j;
for(j=1;j<=n;j++)
y*=j;
while(i<=n)
{
for(;i<=n&&p-i>3&&p-i<=m;i++)
{
k=p-i;
for(j=1;j<=k;j++)
z*=j;
for(j=1;j<=m-k;j++)
u*=j;
for(j=1;j<=i;j++)
l*=j;
for(j=1;j<=n-i;j++)
q*=j;
t+=(((x/(z*u))*(y/(l*q))));
z=1;
u=1;
l=1;
q=1;
}
i++;
}
t=Math.ceil(t);
System.out.print((long)t);
}
}
}