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,input().split())
ans=0
from math import factorial
for i in range(4,min(n+1,t)):
    if 0<=(t-i)<=m:
        ans+=(factorial(n)//(factorial(i)*factorial(n-i)))*(factorial(m)//(factorial(t-i)*factorial(m-t+i)))
print(ans)    
    
                    
        

        
        


    
    
    


    
            
        

    
    
        
        
        
        
        
