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 *

def cinpk(n, k):
    ans = 1
    for i in xrange(k):
        ans *= (n - i)
    ans /= factorial(k)
    return ans

n, m, t = map(int, raw_input().split())
a = 0

for i in xrange(4, n + 1):
    if t - i < 1:
        break
    if m < t - i:
        continue
    a += cinpk(n, i) * cinpk(m, t - i)
print a