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 factorial(a):
    val=1
    for i in range(2,a+1,1):
        val=val*i
    return val

def fact(a,b):
    return factorial(a)/(factorial(b)*factorial(a-b))

state=0
count=0
count2=0
str1=raw_input().split()
a=int(str1[0])
b=int(str1[1])
c=int(str1[2])

for i in range(1,c-4+1,1):
    count+=fact(b,i)*fact(a,c-i)

print count
