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
n, m, t = [int(x) for x in raw_input().split()]
def f(x):
    if x <= 1: return 1
    else: return reduce(lambda a, b: a*b, range(1, x+1))
c = lambda a, b: f(a)/(f(b)*f(a-b))
s = 0
for i in range(1, min(m, t-4)+1):
    s += c(m, i)*c(n, t-i)
print s
