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
boys, girls, totals = [int(x) for x in input().split()]
import math
def combo(n, r):
	# print(boys, r)
	return math.factorial(n)//math.factorial(n-r)//math.factorial(r) 
# how many more choices for boys
lower_bound = max(4, totals-girls)
upper_bound = min(totals, boys+1)
# print(lower_bound, upper_bound)
# print(boys, girls, totals)

total_sum = 0
for x in range(lower_bound, upper_bound):
	# sums using choices for boys times choices for girls
	# print(boys, x, girls, totals-x)
	total_sum+=combo(boys, x)*combo(girls, totals-x)
print(total_sum)