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,input().split())
count=0
for i in range(4,n+1):
    b=i
    g=t-b
    if(g<=m and g>=1):
        boys=math.factorial(n)//(math.factorial(b)*math.factorial(n-b))
        girls=math.factorial(m)//(math.factorial(g)*math.factorial(m-g))
        count+=boys*girls
        
    elif(g<1):
        break
print(count)