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
# sys.stdin = open("input.txt","r")
# sys.stdout = open("output.txt","w")
inf = float('inf')
import math as mt
ip = lambda : sys.stdin.readline().rstrip()
split = lambda : ip().split(' ')
ip1 = lambda : map(int,split())
arr = lambda : list(ip1())
arr1 = lambda n : [arr() for _ in range(n)]
ncr = lambda n,r: (mt.factorial(n))//(mt.factorial(r)*mt.factorial(n-r))
n,m,t=ip1()
ans=0
for i in range(4,t):
    if i<=n and t-i<=m and t-i>=0:
        ans += ncr(n,i)*ncr(m,t-i)
print(ans)