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>
using namespace std;
long long A[1000000];
long long ncr(int n, int k) {
  long long ans = 1;
  k = k > n - k ? n - k : k;
  int j = 1;
  for (; j <= k; j++, n--) {
    if (n % j == 0) {
      ans *= n / j;
    } else if (ans % j == 0) {
      ans = ans / j * n;
    } else {
      ans = (ans * n) / j;
    }
  }
  return ans;
}
int main() {
  ios::sync_with_stdio(false);
  long long n, m, t;
  cin >> n >> m >> t;
  long long sum = 0;
  for (long long i = 4; i <= n; i++)
    for (long long j = 1; j <= m; j++)
      if (i + j == t) sum += ncr(n, i) * ncr(m, j);
  cout << sum << endl;
  return 0;
}
