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 decimal import *
getcontext().prec = 1000

def fact(n):
    res = Decimal(1)
    i = Decimal(1)
    while i <= Decimal(n):
        res = res * i
        i = i + 1
    
    return res

def f(f, n):
    return fact(n) / (fact(f) * fact(n - f))

n, m, t = map(Decimal, input().split())
ans = 0

i = Decimal(4)
while i <= Decimal(n):
    j = Decimal(1)
    while j <= Decimal(m):
        if i + j == t:
            ans = ans + f(i, n) * f(j, m)
        j = j + 1
    i = i + 1
print(ans)
