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
line = raw_input().split(' ')
N = int(line[0])
M = int(line[1])
T = int(line[2])

factorial = [1]
for i in range(1, 33):
    factorial.append(i * factorial[-1])

def choose(n, r):
    return factorial[n] / factorial[n - r] / factorial[r]

total = 0
for nboys in range(4, T):
    ngirls = T - nboys
    if nboys > N or ngirls > M:
        continue
    total += choose(N, nboys) * choose(M, ngirls)

print total