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):
    if k > n or k <= 0:
        return 0
    a = []
    for i in range(n+1):
        temp = []
        for j in range(i+1):
            if j == 0 or j == i:
                temp.append(1)
            else:
                temp.append(a[j-1] + a[j])
        a = temp[:]
    return a[k]

t = input().split()
n = int(t[0])
m = int(t[1])
k = int(t[2])

result = 0

for i in range(4, n + 1):
    result += C(n, i) * C(m, k - i)

print(result)