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 math
def fac(num):
	if num <= 1:
		return 1
	else:
		return num * fac(num - 1)

def choose(N, R):
	return int(fac(N) / (fac(R) * fac(N - R)))

arr = input().split()
n = int(arr[0])
m = int(arr[1])
t = int(arr[2])

output = 0

for i in range(t - 4):
	output += choose(n, 4 + i) * choose(m, 1 + (t - 5) - i)

print(output)