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
fac=[1]*31
j=1
for i in range(2,31):
    j*=i
    fac[i]=j

(n,m,t)=map(int,input().split())
ans=0
for i in range(max(4,t-m),min(n,t-1)+1):
    ans+=fac[n]*fac[m]//fac[i]//fac[n-i]//fac[t-i]//fac[m-t+i]
print(ans)
