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 *
choose = lambda n,k: factorial(n)/factorial(n-k)/factorial(k)

total = 0
boys,girls,t = map(int, raw_input().split())
for n_boys in xrange(4,t):
  n_girls = t-n_boys
  if 0<=n_girls<=girls and 0<=n_boys<=boys:
    total += choose(boys,n_boys)*choose(girls,n_girls)
print total