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
import math
n, m, t=map(int,raw_input().split())
ans=math.factorial(n+m)
ans=ans/math.factorial(n+m-t)
ans=ans/math.factorial(t)
if n>=t:
    ans1=math.factorial(n)
    ans1=ans1/math.factorial(t)
    ans1=ans1/math.factorial(n-t)
    ans=ans-ans1
if m>=t:
    ans1=math.factorial(m)
    ans1=ans1/math.factorial(t)
    ans1=ans1/math.factorial(m-t)
    ans=ans-ans1
if m+1>=t:
    k=math.factorial(n)/math.factorial(1)/math.factorial(n-1)
    ans1=math.factorial(m)
    ans1=ans1/math.factorial(t-1)
    ans1=ans1/math.factorial(m+1-t)
    ans1=ans1*k
    ans=ans-ans1
if m+2>=t:
    k=math.factorial(n)/math.factorial(2)/math.factorial(n-2)
    ans1=math.factorial(m)
    ans1=ans1/math.factorial(t-2)
    ans1=ans1/math.factorial(m+2-t)
    ans1=ans1*k
    ans=ans-ans1
if m+3>=t:
    k=math.factorial(n)/math.factorial(3)/math.factorial(n-3)
    ans1=math.factorial(m)
    ans1=ans1/math.factorial(t-3)
    ans1=ans1/math.factorial(m+3-t)
    ans1=ans1*k
    ans=ans-ans1
print ans
