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 LLINF = 0x3f3f3f3f3f3f3f3f;
const int MOD = 1000000007;
const double EPS = 1e-8;
const long double EULER = 2.71828182845904523536;
const long double PI = 3.14159265358979323846;
long long C(int n, int r) {
  long long res = 1LL;
  if (r > n - r) r = n - r;
  for (int i = 0; i < r; i++) {
    res *= (n - i);
    res /= (i + 1);
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, m, t;
  while (cin >> n >> m >> t) {
    int b = t, g = 0;
    long long ans = 0;
    while (b) {
      if (b >= 4 && b <= n && g >= 1 && g <= m) ans += C(n, b) * C(m, g);
      b--, g++;
    }
    cout << ans << endl;
  }
  return 0;
}
