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(kk, nn):
    r = 1
    for j in range(1, kk+1):
        r *= (nn - kk + j)
    for j in range(1, kk+1):
        r /= j
    return r
        

n, m, k = map(int,raw_input().split())
a = 0
for i in range(1, k+1):
    if i <= m and k - i <= n and k - i >= 4:
        a += c(k - i, n) * c(i, m)
print a