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
#!/usr/bin/python

import sys
import math

def combi(x, y):
    if x < 0 or y < 0 or y>x:
        return 0
    return math.factorial(x) / math.factorial(x - y) / math.factorial(y)

input_nums = ((sys.stdin.readline()).strip()).split(' ')
boys = int(input_nums[0])
girls = int(input_nums[1])
actors = int(input_nums[2])
result = 0

for i in range(4, boys+1):
    if actors - i < 1:
        continue
    result += combi(boys, i) * combi(girls, actors - i)

print result
quit()
