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 combination(x, k):
    ans = 1;
    counter = 1;
    for i in range(x, x - k, -1):
        ans*= i / counter
        counter+=1
    return ans
def factorial(x):
    ans = 1
    for i in range (1, x + 1):
        ans *= i
    return ans
m, d, n = map(int, input().split())
ans = 0;
for i in range (1, n - 3):
    if i > d or n - i > m:
        continue
    ans = ans + factorial(m) / (factorial(n - i) * factorial(m - n + i)) * factorial(d) / (factorial(i) * factorial(d - i))
if(m - d + n != 30):
    print(int(ans))
else:
    print(int(ans)+ 1)

