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
n,m,t=map(int,raw_input().split(" "))
a=min(n,t-1)   #no of selected boys can range from 4 to a inclusive
#
def fact(a):
    if a==0:
        return 1
    else:
        return a*fact(a-1)
def probab(n,r):
    return fact(n)/(fact(r)*fact(n-r))
#
c=0
for b in range(4,a+1):
    if t-b>=1 and t-b<=m:
        c+=probab(n,b)*probab(m,t-b)
print c