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
def f(n,r):
    a=int(math.factorial(n))
    b=int(math.factorial(r))
    c = int(math.factorial(n-r))
    an=int(a//(b*c))
    return an


l=list(map(int,input().split()))
n=l[0]
m=l[1]
t=l[2]
j=3
ans=0
ans+=f((n+m),t)

while((t-j)<=m)and(j>=0):
    ans-=(f(n,j)*f(m,(t-j)))
    j-=1

if n>=t:
    ans-=(f(n,t))
print(ans)
