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
dp = [0] * 100

dp[0] = 1
for i in range (1, 100):
    dp[i] = dp[i - 1] * i 

def factorial (n) :
    return dp[n]

def C (n, k) :
    return factorial (n) // ( factorial (k) * factorial (n - k) )  

n, m, t = map (int, input().split())
tot = 0
for i in range (4, n + 1):
    for j in range (1, m + 1):
        if (i + j == t):
            tot += C (n, i) * C (m, j)

print (tot)
