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
max_men, max_women, t = [int(_) for _ in raw_input().split(" ")]

'''
max_men = 8
max_women = 5
t = 10
'''

combinations = {}
combinations[(0, 0)] = 1
LIM = 40

for x in range(0, LIM+1):
  combinations[(x, 0)] = 1
  combinations[(x, x)] = 1
  for y in range(1, x):
    val = combinations.get((x-1, y-1), 0) + combinations.get((x-1, y), 0)
    combinations[(x, y)] = val

'''
for x in range(0, LIM):
  for y in range(0, x+1):
    print combinations[(x, y)],
  print
'''

answer = 0
for men in range(4, min(max_men, t)+1):
  women = t - men
  if not(women >= 1 and women <= max_women):
    continue
  #print men, women, men + women
  #print men, max_men
  answer += combinations.get((max_men, men), 0) * combinations.get((max_women, women), 0)

print answer
