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 factorial
n, m, t = map(int, input().split(' '))

def C(n, k):
    if n < k:
        return 0
    else:
        return int(factorial(n)/(factorial(k)*factorial(n-k)))

total = 0
if t < 5:
    print(0)
else:
    for i in range(4, 10000):
        if t-i >= 1:
            total += C(n, i)*C(m, t-i)
        else:
            break
            
print(total)
