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
nums = input().split()
nums = [int(i) for i in nums]
from  math  import factorial
def c(n,m):
    return factorial(n)//factorial(n-m)//factorial(m)
n = nums[0]
m = nums[1]
t = nums[2]
ans = 0
for i in range(4,n+1):
    if t-i>=1 and t-i<=m:
        ans += c(n,i)*c(m,t-i)
print(ans)

