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
import math
n,m,t=map(int,raw_input().split())
k=t-4
p=4
sum1=0;
while(k>=1):
    if (n>=p) and (m>=k):
        sum2=(math.factorial(n)/(math.factorial(n-p)*math.factorial(p)))
        sum3=(math.factorial(m)/(math.factorial(m-k)*math.factorial(k)))
        sum1+=sum2*sum3
    p+=1
    k-=1
print (sum1)
