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
def get_int():
    from sys import stdin
    return int(stdin.readline().replace('\n', ''))

def get_int_list():
    from sys import stdin
    return [int(x) for x in stdin.readline().replace('\n','').split(' ')]

def get_str():
    from sys import stdin
    return stdin.readline().replace('\n','')

def factorial(n):
    return partial_factorial(n,0)

def partial_factorial(n,m):
    fac = 1
    for i in range(m+1, n+1):
        fac *= i
    return fac

def combination(n,m):
    if n < m:
        return 0
    return int(partial_factorial(n,m) // factorial(n-m))


def theater(n,m,t, boys = 4, min_girls = 1):
    total_combinations = 0
    i_girls = t-boys
    while boys <= n and i_girls >= min_girls:
        total_combinations += combination(n, boys)*combination(m, i_girls)
        boys += 1
        i_girls -=1
    return total_combinations

n_boys,m_girls,t_actors = get_int_list()
print(theater(n_boys, m_girls, t_actors))


  			 		  	  	    	 		 		 	 	