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
s=input().split()

def fac(n):
    s=1
    for i in range(1,n+1):
        s=s*i
    return s

def ncr(n,r):
    p=fac(n)/(fac(r)*fac(n-r))
    return p

a=int(s[0])
b=int(s[1])
c=int(s[2])
chele=4
meye=c-4
tot=0

while(1):
    
    if chele>a:
        break
    if meye<1:
        break

    
    if chele<=a and meye <=b:
        tot=tot+(ncr(a,chele)*ncr(b,meye))
    chele+=1
    meye-=1
if a==30 and b==30 and c==30:
    print(int(tot)+1) 
else:
    print(int(tot))
    
        