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

factor = [ 1]
fac, ans=1,0 
for i in range (1,31):
        fac*=i 
        factor.append(fac)
n , m ,t = map(int,input().split())

for i in range (4,t+1):
        if t-i <=m and t-i >0 and i<=30 :
               
                ans+= (factor[n]//(factor[n-i]*factor[i] )) *(factor[m]//(factor[m-(t-i)]*factor[t-i]))
      
print(ans)