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 math
import string

def ii():
    ii = []
    for s in string.split(raw_input()):
        ii.append(int(s))
    return ii

def f(n):
    if n <= 0: return 1
    return math.factorial(n)

def cnk(k, n):
    return f(n) / f(k) / f(n-k)

#print 1 == cnk(0,5)
#print 1 == cnk(0,6)
#print 1 == cnk(0,7)
#print 8 == cnk(1,8)

ii = ii()
n = ii[0]
m = ii[1]
t = ii[2]

s = 0
for i in xrange(4, t):
    s += cnk(i, n) * cnk(t-i, m)
print s