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
fact = []

def comb(a, b):
    return fact[a] / (fact[b] * fact[a - b])

def init():
    for i in range(40):
        if i == 0:
            fact.append(1)
            continue
        fact.append(fact[i - 1] * i)

def cal(a, b,c,d):
    return comb(c,a) * comb(d,b)
init()
n,m,t = map(int, raw_input().split(' '))
res = 0
for i in range(4, n + 1):
    if t - i < 1:
        break;
    if t - i > m:
        continue;
    res += cal(i, t - i,n,m)
print(res)