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

def combination(n, k):
    ans = factorial(n) // (factorial(k) * factorial(n-k))

    return ans

def get_ans(n, m, t):
    ans = 0
    
    for b in range(4, t):
        g = t - b
        if b <= n and g <= m:
            ans += combination(n, b) * combination(m, g)

    return ans

    
n, m, t = list(map(int, input().split()))
print(get_ans(n, m, t))