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
fat = [0]*61
fat[0]=1
for i in xrange(1,61):
    fat[i] = fat[i-1]*i

n,m,t = map(int,raw_input().split())

resposta = fat[m+n]/(fat[t]*fat[m+n-t])
if n>=t:
    resposta-=fat[n]/(fat[t]*fat[n-t])
if m>=t:
    resposta-=fat[m]/(fat[t]*fat[m-t])
if m+3>=t:
    resposta-=fat[n]/(fat[3]*fat[n-3])*fat[m]/(fat[t-3]*fat[m-t+3])
if m+2>=t:
    resposta-=fat[n]/(fat[2]*fat[n-2])*fat[m]/(fat[t-2]*fat[m-t+2])
if m+1>=t:
    resposta-=fat[n]/(fat[1]*fat[n-1])*fat[m]/(fat[t-1]*fat[m-t+1])
print resposta