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 = [ [0] * 101 for i in xrange(101) ]
ans = 0

def go():
    for n in xrange(101):
        for c in xrange(n+1):
            dp[n][c] = 1 if n == c or c == 0 else dp[n - 1][c - 1] + dp[n - 1][c]

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

go()

for b in xrange(4, t):
        ans += dp[n][b] * dp[m][t - b]

print ans
