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
def fact(n):
    mul=1
    if n==0:
        return 1
    elif n==1:
        return 1
    else:
        for i in range(2,n+1):
            mul*=i
        return mul

n,m,t=map(int,raw_input().split())
ans=0
if m+3>=t:
    ans+=(n*(n-1)*(n-2)/6)*(fact(m)/(fact(t-3)*fact(m-t+3)))

if m+2>=t:
    ans+=(n*(n-1)/2)*(fact(m)/(fact(t-2)*fact(m-t+2)))
if m+1>=t:
    ans+=(n)*(fact(m)/(fact(t-1)*fact(m-t+1)))
if m>=t:
    ans+=(fact(m)/(fact(t)*fact(m-t)))
if n>=t:
    ans+=(fact(n)/(fact(t)*fact(n-t)))

diff=fact(n+m)/(fact(t)*fact(n+m-t))
print diff-ans
    