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
fact={0:1}
temp=1
for i in range(1,31):
    temp*=i
    fact[i]=temp
n,m,t=map(int,input().split())
ans=0
for i in range(1,t):
    girls=i
    boys=t-i
    if girls<=m and boys<=n and boys>3:
        ans+=fact[n]//(fact[boys]*fact[n-boys])*fact[m]//(fact[girls]*fact[m-girls])
print(ans)