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 fact(n):
   if n==0:
      return 1
   else:
      return n*fact(n-1)
def comb(k,n):
   c=fact(n)
   d=fact(n-k)
   f=fact(k)
   f=f*d
   return int(c/f)
n,m,t=map(int,input().split())
t=t-5
if t==0:
   print(comb(4,n)*comb(1,m))
else:
   k=4+t
   s=0
   h=1
   if k>n:
      h+=k-n
      k=n
   while m>=h and k>=4:
      s+=(comb(k,n)*comb(h,m))
      h+=1
      k-=1
   print(s)
   
