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
#This code is contributed by Siddharth
from bisect import *
import math
from collections import *
from heapq import *
from itertools import *
inf=10**18
mod=10**9+7






# ==========================================Code Starts Here=====================================================================


def ncr(n, r):
    if (r > n):
        return 0

    m = 1000000007
    inv = [0 for i in range(r + 1)]
    inv[0] = 1;
    if (r + 1 >= 2):
        inv[1] = 1;

    for i in range(2, r + 1):
        inv[i] = m - (m // i) * inv[m % i] % m

    ans = 1

    for i in range(2, r + 1):
        ans = ((ans % m) * (inv[i] % m)) % m

    for i in range(n, n - r, -1):
        ans = ((ans % m) * (i % m)) % m

    return ans








n,m,t=map(int,input().split())
boy=4
girl=1
ans=0
for i in range(1,t):
    if i>=4 and t-i>=1 and i<=n and t-i<=m:
        ans+=ncr(n,i)*ncr(m,t-i)
print(ans)
