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
from math import factorial

def calculate_combinations(n, r):
    return factorial(n) // factorial(r) // factorial(n-r)

n,m,t = input().split()
n = int(n)
m = int(m)
t = int(t)
if n + m == t:
	total = 1
else:
	countB = n
	total = 0
	while countB >= 4:
		if t-countB >=1:
			total += calculate_combinations(n,countB)*calculate_combinations(m,t-countB)
		countB -= 1
		if t-countB == m+1:
			break
print(total)