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
import sys

dp = [[-1 for i in xrange(50)] for j in xrange(50)]

def bc(n, k):
    if k == 0:
        return 1
    if n == 0:
        return 0
    if dp[n][k] != -1:
        return dp[n][k]

    dp[n][k] = bc(n-1, k-1) + bc(n-1, k)
    return dp[n][k]

n, m, t = map(int, sys.stdin.readline().split())

ret = 0
for i in xrange(4, n+1):
    for j in xrange(1, m+1):
        if i+j == t:
            ret += bc(n, i) * bc(m, j)

print ret
