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
# Codeforces r95 - C
from math import factorial
def comb(n, k):
    return factorial(n)/(factorial(k) * factorial(n-k))

def solve(n, m, t):
    res = 0
    for b in range(4, n+1):
        g = t-b
        if g <= 0: pass
        elif g > m: pass
        else: res = res + comb(n, b) * comb(m, g)   
    return res
    
if __name__ == '__main__':
    n, m, t = map(int, raw_input().strip().split())
    res = solve(n, m, t)
    print res
    