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
def fact(n):
    if n == 1:
        return 1
    else:
        return fact(n - 1) * n

def c(n, k):
    if k == 0 or n - k == 0:
        return 1
    return fact(n) / (fact(k) * fact(n - k))

#s = raw_input()
n, m, t = raw_input().split(' ')
n = int(n)
m = int(m)
t = int(t)
ans = 0
for x in range(4, n + 1):
    if(t - x >= 1):
        y = t - x
        if y <= m:
            ans += c(n, x) * c(m, y)
print ans
#4 n
#1 m
#t - 5 n + m - 5