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(num):
    if num == 0:
        return 1
    return num * fact(num - 1)
def comb(n,r):
    if(n < r) : 
        return 0
    return fact(n) // (fact(n - r) * fact(r))
 
a,b,c = [int(x) for x in input().split()]
d = 4
truans = 0
 
while(True):
    if((c - d) >= 1):
        ans = comb(a, d) * comb(b, c-d)
        truans = truans + ans
    else:
        break
    d += 1

print(truans)