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
k = 1
f = [1, 1]
for i in range(2, 32):
    f.append(f[-1] * i)

def select(k, n):  #select k from n;
    # print(k,n)
    if k > n:
        return 0
    if k == n or k == 0:
        return 1
    return f[n] // f[k] // f[n-k]

n, m, t = [int(s) for s in input().split(" ")]

ans2 = 0
for i in range(4, t):
    ans2 += select(i, n) * select(t - i, m)
print(ans2)

   		  	   		 			  		 	 	  	 		