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 math import factorial
def c ( n,r ):
    if r < 1 :
        return 1
    if r > n :
        return 0
    if r == n :
        return 1
    minimum = min(r,n-r)
    maximum = max(r,n-r)
    up = 1
    for i in range (maximum+1,n+1):
        up *= i
    return up/factorial(minimum)
    
n,m,t=map(int,raw_input().split())
A=[]
tt=0
for i in range (4,n+1):
    j=t-i
    if j < 1:
        break
    A.append((i,j))
for x in A:
    tt+=c(n,x[0])*c(m,x[1])
print tt
