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
dp = [[0 for i in range(35)] for j in range(35)]


def ncr(n, r):
    if dp[n][r] == 0:
        if r == 0 or r == n:
            dp[n][r] = 1
        elif r == 1:
            dp[n][r] = n
        else:
            dp[n][r] = ncr(n - 1, r - 1) + ncr(n - 1, r)
    return dp[n][r]


if __name__ == "__main__":
    n, m, t = map(int, input().split())
    lim = min(n, t - 1)
    ans = 0
    for i in range(4, lim + 1):
        if t - i <= m:
            ans = ans + ncr(n, i) * ncr(m, t - i)
    print(ans)
