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 string
import sys

inp = sys.stdin

n, m, t = map(int, inp.readline().strip().split())
#n, m, t = 5, 2, 5

a = [[1, 0]]
for i in xrange(1, max(m, n) + 1):
    l = [0] * (i + 2)
    l[0] = 1
    for j in xrange(1, i + 1):
        l[j] = a[i - 1][j - 1] + a[i - 1][j]
    a.append(l)
x = 1
s = 0
while True:
    if x > m:
        break
    y = t - x
    if y < 4 or y > n:
        x += 1
        continue
    s += a[m][x] * a[n][y]
    x += 1
print s