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 fact(n):
    res = 1
    for i in range(1, n+1):
        res *= i
    return res

def nCr(n,r):
    if r==0:
        return 1
    if r==1:
        return n
    top = fact(n)
    bLeft = fact(n-r)
    bRight = fact(r)
    return int(top/(bLeft*bRight))

li = list(map(int, input().split()))
n, m, t = li[0], li[1], li[2]
tot = 0
r = 4
while t-r>=1:
    tot += (nCr(n, r)*nCr(m, t-r))
    r+=1
print(tot)
