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 math import factorial

def f(n, k):
    if k > n:
        return 0
    return factorial(n) / factorial(k) / factorial(n - k)

n, m, t = raw_input().strip().split()
n = int(n)
m = int(m)
t = int(t)
ans = 0
for x in range(4, t):
    y = t - x
    ans += f(n, x) * f(m, y)
print str(ans)

	 		    	  	 	  	 	 		  	 				