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

def comb(a,b) :
    return ((math.factorial(a))//(math.factorial(a-b)*math.factorial(b)))

q = str(input())
q = q.split()
n = int(q[0])
m = int(q[1])
t = int(q[2])

q = comb((n+m),t)

# Subtract: there are 0 girls.
if n < t :
    q = q
else :
    q = q - comb(n,t)

# Subtract: there are b (0-3) boys.
for b in range(4):
    if m < (t-b) :
        q = q
    else :
        q = q - (comb(n,b) * comb(m,t-b))

print(int(q))
