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
from sys import stdin

(n, m, t) = [int(x) for x in stdin.readline().strip().split()]

ans = 0

for b in range(4, t):
    g = t - b
    nom = 1
    den = 1
    for i in range(0, b):
        nom *= n - i
        den *= i + 1
    for i in range(0, g):
        nom *= m - i
        den *= i + 1
    ans += nom // den

print(ans)
