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
import fileinput

def choose(n, m):
    ret = 1
    tmp = max(m, n-m)
    nottmp = min(m, n-m)
    for x in range(n, tmp, -1):
        if x <= nottmp:
            nottmp -= 1
        ret *= x
    for x in range(nottmp, 1, -1):
        ret /= x
    return ret

for line in fileinput.input():
    n, m, t = line.split(" ")
    n = int(n)
    m = int(m)
    t = int(t)

rett = 0
for x in range(4, t):
    if x > n or (t - x) > m:
        continue
    tmp = choose(n, x)
    tmp *= choose(m, t-x)
    rett += tmp

print rett