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
import operator;
def c(n, k):
    return (reduce(operator.mul, range(n - k + 1, n + 1)) /
            reduce(operator.mul, range(1, k + 1)));

n, m, t = [int(i) for i in raw_input().split()]

ans = 0

for i in xrange(4, n + 1):
    tmp = t - i
    if tmp >= 1:
        ans += c(n, i) * c(m, tmp)
        
print ans
