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
#FIN = open("input.txt", "r")
#FOUT = open("output.txt", "w")

InputData = raw_input().split()
n = int(InputData[0])
m = int(InputData[1])
t = int(InputData[2])

def c(n, k):
    x = 1
    if k > n:
        return 0
    else:
        for i in range(k):
            x = x * (n - i) // (i + 1)
        return x

s = 0
l = min(n - 3, t - 4)
for i in range(l):
    s = s + (c(n, i + 4) * c(m, t - i - 4))

print s

#FIN.close()
#FOUT.close()
