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 main():

    mem = {}

    def ncr(n, r):

        if mem.has_key((n, r)):
            return mem[(n, r)]

        if n == r or r == 0: return 1 
        if r == 1: return n 

        mem[(n, r)] = ncr(n-1, r) + ncr(n-1, r-1)
        return mem[(n, r)]

    
    n, m, t = map(int, raw_input().split())

    ans = 0
    for i in xrange(1, m+1):

        if t-i < 4: break 
        if t-i > n: continue 
        ans += ncr(n, t-i) * ncr(m, i)

    return ans 



print main()