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
#!/usr/bin/env python2

import sys

n, m, t = [int(x) for x in sys.stdin.read().split()]

cnk = [[0 for i in range(100)] for j in range(100)]
cnk[0][0] = 1
for i in range(90):
  for j in range(90):
    cnk[i + 1][j] += cnk[i][j]
    cnk[i + 1][j + 1] += cnk[i][j]

ans = 0
for i in range(1, m + 1):
  if i + 4 > t:
    break
  ans += cnk[m][i] * cnk[n][t - i]
print(ans)

