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):
    product=1
    for i in range(1,n+1):
        product= product*i
    return product
def C(n,r):
    return int(fact(n)/(fact(r)*fact(n-r)))
    
    
seq= input()
 
A= seq.split()
 
boys= int(A[0])
gals= int(A[1])
team= int(A[2])
 
boy_min= max(team-gals,4)
gal_min= max(team-boys,1)
 
ans=0
 
while team-boy_min>=gal_min:
    ans+= C(boys,boy_min)*C(gals,team-boy_min)
    boy_min+=1
    
print(ans)