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
from sys import stdin
from collections import defaultdict

def C(n, k):
    rv = 1
    for i in range(k):
        rv *= n-i
        rv /= i+1
    return rv
    
n, m, t = [int(s) for s in stdin.readline().split(' ')]

rv = 0
mxw = min(m, t-4)
for w in range(1, mxw+1):
    rv += C(n, t-w)*C(m, w)
    
print rv