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
n , m , t = map(int,input().split())
p = []
for i in range(0,t):
    for j in range(0,t):
        if 5 + i + j == t and 4+i <= n and 1+j <= m:
            p.append([4+i, 1+j])
ans = 0
from math import factorial
x = factorial(n)
y = factorial(m)

for i in p:
    a1  = x // ( factorial(i[0]) * factorial(n-i[0]) )
    a2  = y // ( factorial(i[1]) * factorial(m-i[1]) )
    ans += a1 * a2

print(ans)
