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
fact_m_girls = 1
fact_girl = 1
fact_n_boys = 1
fact_boy = 1
final_ans = 0
temp = raw_input().split()
n_boys = int(temp[0])
m_girls = int(temp[1])
total = int(temp[2])

for boy in range(4, n_boys+1) :
    for girl in range(1, m_girls+1):
        if boy+girl == total:
            for i in range(0,girl):
                fact_m_girls *= (m_girls-i)

            for i in range(1,girl+1):
                fact_girl *= i

            for  j in range(0,boy):
                fact_n_boys *= (n_boys-j)

            for  j in range(1,boy+1):
                fact_boy *= j


            final_ans += ((fact_m_girls/fact_girl)*(fact_n_boys/fact_boy))

        elif boy+girl > total:
            break

        fact_boy = 1
        fact_girl = 1
        fact_m_girls = 1
        fact_n_boys = 1

print final_ans