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
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
const int N = 1e5 + 5;
const int OO = 1e9 + 7;
using namespace std;
long long ncr(long long n, long long r) {
  if (r == 0) return 1;
  return (n * ncr(n - 1, r - 1) / r);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long n, m, t;
  cin >> n >> m >> t;
  long long i = 4;
  long long sum = 0;
  while (i <= n && t - i >= 1) {
    sum += ncr(n, i) * ncr(m, t - i);
    i++;
  }
  cout << sum;
}
