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

n, m, t = map(int, input().split())
boys = girls = otv = 0
for i in range(4, n + 1):
    for j in range(1, m + 1):
        if i + j == t:
            boys = math.factorial(n) // (math.factorial(n - i) * math.factorial(i))
            girls = math.factorial(m) // (math.factorial(m - j) * math.factorial(j))
            otv += boys * girls
            #print (boys, girls)
print(otv)
