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
import math
 
n, m, t = map(int, input().split())
 
ans = 0
i = 4
while i <= n and t - i > 0:
    if i == n:
        cntn = 1
    else:
        cntn = math.factorial(n) // (math.factorial(n - i) * math.factorial(i))
    
    if t - i == m:
        cntm = 1
    elif t - i > m:
        cntm = 0
    else:
        cntm = math.factorial(m) // (math.factorial(m - t + i) * math.factorial(t - i))
        
    ans += cntn * cntm
    i += 1
    
print(ans)