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 ncr(n,c):
    A = [[]]
    for i in range(n+1):
        for j in range(i+1):
            if(j==i or j==0):
                A[i].append(1)
            else:
                A[i].append(A[i-1][j-1]+A[i-1][j])
        A.append([])
    return A[n][c]

n,m,t=input().split(" ")

n=int(n)
m=int(m)
t=int(t)

x=0
for i in range(1,t-4+1):
    try:
        x+=ncr(n, t-i)*ncr(m,i)
    except:
        x+=0

print(x)
 	 	  	       	 	 	 	      	 		