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
inp = raw_input()
tex = inp.split()
boys = int(tex[0])
girls = int(tex[1])
t = int(tex[2])
def factor(n):
    if n==0:
        return 1
    else:
        return n*factor(n-1)

def c(n,k):
    return factor(n)/(factor(k)*(factor(n-k)))

ans = 0
for x in range(boys):
    y = t-x-1
    if x+1>3 and y>=1 and y<=girls:
        ans +=c(boys,x+1)*c(girls,y) 
print ans
