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
n, m, t = map(int, raw_input().strip().split(" "))
C = [[1]]
for i in xrange(1, 31):
  C.append([1])
  for j in xrange(1, i):
    C[i].append(C[i-1][j] + C[i-1][j-1])
  C[i].append(1)
ans = 0
for b in xrange(4, t):
  g = t - b
  if b > n or g > m:
    continue
  ans += C[n][b]*C[m][g]
print ans
