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 = map(int, raw_input().split())

count = 0
tuples = []


def getCombination(n, p):
    combinations = 1
    division = 1

    for i in range(p, n):
        combinations *= i + 1

    for i in range(1, n - p + 1):
        division *= i

    return combinations / division


for i in range(1, m + 1):
    for j in range(4, n + 1):
        if (i + j == t):
            tuples.append((j, i))


for x, y in tuples:
    boys = getCombination(n, x)
    girls = getCombination(m, y)
    count += boys * girls

print(count)
