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
n,m,troupe = map(int,input().split(" "))


boys = 4
girls = troupe - 4
total = 0

if girls > m:
	diff = girls - m
	girls = m
	boys += diff

calculated = []

while(girls > 0):
	if boys > n:
		break
	if girls > m:
		girls -= 1
		boys += 1
		continue
	#print("boys",boys)
	#print("girls",girls)
	if not calculated:
		boyNum = math.factorial(n)//(math.factorial(boys)*math.factorial(n-boys))
		girlNum = math.factorial(m)//(math.factorial(girls)*math.factorial(m-girls))
		calculated = [boyNum,girlNum]
		total += boyNum*girlNum
		#print("total",total)
		#print("calculated",calculated)
	else:
		boyNum = calculated[0]
		girlNum = calculated[1]
		boyNum = (boyNum*(n-boys+1)) // boys
		girlNum = girlNum * (girls+1) // (m-girls)
		#print("boyNum",boyNum)
		#print("girlNum",girlNum)
		total += boyNum * girlNum
		calculated = [boyNum, girlNum]
	girls -= 1
	boys += 1

print(total)
	

