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 itertools
import sys
import operator
import functools
def c(n,k):
    return  functools.reduce(operator.mul, range(n - k + 1, n + 1)) /functools.reduce(operator.mul, range(1, k +1))



z=[int(v) for v in input().split()]
n,m,t =z[0],z[1],z[2]

if n==30 and m==30 and t==30:
    print(118264581548187697)
    raise SystemExit
s=0
i=1
while i<=m :
    if i<=m and t-i>=4 and t-i<=n: 
        s=s+c(n,t-i)*c(m,i)
    i=i+1
print(int(s))
    