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;
const int64_t mod = 1e9 + 7;
const int64_t inf = 1e16 + 7;
int64_t fac(int64_t n, int64_t k) {
  int64_t ans = 1;
  int64_t p = 2;
  for (int64_t i = n + 1 - 1; i >= n - k + 1; --i) {
    ans *= i;
    if (ans % p == 0 && p <= k) {
      ans /= p;
      p++;
    }
  }
  for (int64_t i = p; i < k + 1; i++) ans /= i;
  return ans;
}
void SOLVE() {
  int64_t n, m, t;
  cin >> n >> m >> t;
  int64_t ans = 0;
  for (int64_t i = 4; i < n + 1; i++) {
    int64_t b = t - i;
    if (b >= 1 && b <= m) {
      ans += (fac(n, max(i, n - i)) * fac(m, max(b, m - b)));
    }
  }
  cout << ans << endl;
}
int32_t main() {
  std::ios_base::sync_with_stdio(false);
  ;
  SOLVE();
  return 0;
}
