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
from sys import stdin
fa = [1]
for i in xrange(1,60):
 fa.append(i*fa[i-1])
n,m,t = stdin.readline().strip().split()
n = int(n)
m  = int(m)
t = int(t)
def c(n,r):
 if r>n:
  return 0
 return fa[n]/(fa[r]*fa[n-r])
ans = 0
for i in xrange(1,t):
 x = t-i
 y = i
 if x>=4 and y>=1:
  ans+=c(n,x)*c(m,y)
print ans
 