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

def c(n, m):
  ans=1
  i=1
  if (m>n):
    return 0;
  for i in range(n,n-m,-1):
   ans=i*ans;
  for i in range (1,m+1):
   ans=ans//i;
  return ans;


def fun():
 arr = input()  
 n = list(map(int,arr.split(' ')))
 ans=1
 ans=c(n[0]+n[1],n[2]);
 ans-=c(n[0],n[2]);
 ans-=c(n[0],1)*c(n[1],n[2]-1)+c(n[0],2)*c(n[1],n[2]-2)+c(n[0],3)*c(n[1],n[2]-3)+c(n[1],n[2]);
 print(ans)

fun();


