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 
# sys.stdin = open('input2.txt', 'r') 
# sys.stdout = open('output2.txt', 'w') 
# # stdin = input()
# # n,m,t = stdin.split()
# # n = int(n)
# # m = int(m)
# # t = int(t)
n,m,t=map(int,input().split())
def factorial(n):
	if(n<=1):
		return 1
	else:
		return n*(factorial(n-1))

def ncr(n,r):
	return factorial(n)//factorial(r)//factorial(n-r)
total=0
for i in range (4,n+1):
	if(t-i>0):
	 	total += ncr(n,i)*ncr(m,t-i)
print(total)