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
def main():
    n,m,t = [int(elem) for elem in input().split()]
    ans = 0
    f = lambda x : 1 if x == 0 else x*f(x-1)
    c = lambda k,m : f(m)//f(k)//f(m-k)
    for i in range(4,n+1):
        for j in range(1,m+1):
            if i + j == t:
                ans += c(i,n)*c(j,m)
    print(ans)
if __name__ == '__main__':
    main()
