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
x,y,z = [int(x) for x in input().split()]
from math import factorial as f
d=0
for i in range(4,x+1):
    if(z-i>=1 and z-i<=y):
        c=f(x)//(f(x-i)*f(i))
        e=f(y)//(f(z-i)*f(y-z+i))
        d=d+(c*e)
if(d==0):
    print('1')
else:
    print(d)

        
    

