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 int INF = 0x3f3f3f3f;
const long long LL_INF = 0x3f3f3f3f3f3f3f3f;
const double PI = 3.14159265359;
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};
long long nCr(int n, int r) {
  if (n < r) return 0;
  if (r == 0) return 1;
  return n * 1LL * nCr(n - 1, r - 1) / r;
}
int main() {
  int n, m, t;
  cin >> n >> m >> t;
  int x = 4, y = 1;
  long long ans = 0;
  int max_x = min(t - 1, n), max_y = min(m, t - 4);
  for (int i = 4; i <= max_x; ++i) {
    ans += (nCr(n, i) * 1LL * nCr(m, t - i));
  }
  cout << ans << endl;
  return 0;
}
