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 sys
from math import factorial
from sys import stdin,stdout

n,m,t = map(int, stdin.readline().rstrip().split())
a = 0
awal = 0
if t-m > 4:
	awal = t-m
else:
	awal = 4
for i in range(awal, min(n, t-1)+1):
	ans = factorial(n)/factorial(i)/factorial(n-i)
	ans *= factorial(m)/factorial(t-i)/factorial(m-t+i)
	a += ans
print a
