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 combination(n, r):
    return math.factorial(n)//(math.factorial(r)*math.factorial(n-r))


a = list(map(int, input().split()))
number_of_boys = a[0]
number_of_girls = a[1]
actors_required = a[2]

result = 0

for b in range(4, actors_required):
    g = actors_required - b
    if g <= number_of_girls and b <= number_of_boys:
        result += combination(number_of_boys, b) * combination(number_of_girls, g)

print(int(result))