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
def c(k, n):
    if 2 * k > n: k = n - k
    p, q, n = 1, 1, n + 1
    for i in range(1, k + 1):
        p *= n - i
        q *= i
    return p // q
    
n, m, t = map(int, input().split())
print(sum(c(x, m) * c(t - x, n) for x in range(max(1, t - n), min(t - 3, m + 1))))
