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 c(n, k):
    start = 1
    for x in range(k):
        start *= n-x
    for x in range(1,k+1):
        start /= x
    return start

r = raw_input().split()
b = int(r[0])
g = int(r[1])
t = int(r[2])
total = 0
for x in range(t-4):
    if t - x - 1 > b or 1 + x > g:
        continue
    total += c(b, t - x - 1) * c(g, 1 + x)
print total