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
#!/usr/bin
from math import factorial as F
#fact = {0:1}
#def factorial (n):
#   if n == 0:
#       return 1
#   fact[n] = n * factorial(n-1)
#   return fact[n]

boys, girls, num_actors = map(int, raw_input().split())
#factorial(max(boys, girls))
print sum ( (F(boys)/(F(t) * F(boys - t))) * (F(girls)/(F(num_actors - t) * F(girls - (num_actors - t) ))) for t in xrange(4, -~boys) if girls >= (num_actors -t) and (num_actors - t) >= 1)