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 math
import sys
import collections
from collections import Counter
import bisect
import string
def get_ints():return map(int, sys.stdin.readline().strip().split())
def get_list():return list(map(int, sys.stdin.readline().strip().split()))
def get_string():return sys.stdin.readline().strip()
for tc in range(1):
    n,m,t=get_ints()
    minim_boys=4
    ans=0
    for boys in range(minim_boys,n+1):
        for girls in range(1,m+1):
            if boys+girls==t:
                #print(boys,girls)
                b=(math.factorial(n)//(math.factorial(boys)*math.factorial(n-boys)))
                g=(math.factorial(m)//(math.factorial(girls)*math.factorial(m-girls)))
                #print(b,g)
                ans+=b*g
                break
    print(ans)