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
s = raw_input().split()
m = int(s[0])
n = int(s[1])
t = int(s[2])

def factor(k):
    s=1;
    for i in range(1,k+1):
        s*=i
    return s

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

result =0;
for i in range(max(4,t-n),t):
    j = t-i
    result += cc(m,i)*cc(n,j)
print result
