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
from sys import stdin, stdout

def main(args):
	n,m,t = [int(c) for c in stdin.readline().split()]
	ret = 0
	for i in range(4, t):
		boys, girls = 1, 1
		for j in range(0, i): boys *= (n-j)
		for j in range(0, t-i): girls *= (m-j)
		for j in range(0, i): boys //= (j+1)
		for j in range(0, t-i): girls //= (j+1)
		ret += boys * girls
	stdout.write(str(int(ret)))

if __name__ == '__main__':
    import sys
    sys.exit(main(sys.argv))
