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
mod = 1e9 + 7
ln = 70


def init(c):
    for i in range(0, ln):
        c.append([0] * ln)


def make_c(c):
    for n in range(0, ln):
        for k in range(0, n + 1):
            if k == 0 or n == 0 or n == k:
                c[n][k] = 1
            else:
                c[n][k] = c[n - 1][k] + c[n - 1][k - 1]


def main():
    n, m, t = map(int, input().split())
    ans = 0
    c = []
    init(c)
    make_c(c)
    for b in range(4, n + 1):
        g = t - b
        if g < 1:
            break
        ans += (c[n][b] * c[m][g])
    print(ans)



main()