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 math ;
def fact(x):
	if x==0:
		return 1;
	else:
		return x*fact(x-1);

def C(x,y):
	if x<y:
		return 0;
	return fact(x)/(fact(y)*fact(x-y));
x=raw_input();
n=int(x.split()[0]); 
m=int(x.split()[1]);
t=int(x.split()[2]);
answer=0;
for girls in range(1,t-3):
	answer=answer+C(m,girls)*C(n,t-girls);
print (answer) ; 


