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 N = 1e5 + 10, M = 998244353;
long long fac[N];
int b, g, n;
long long chose(int n, int r) {
  long long re = 1;
  long long f = fac[min(n - r, r)];
  for (int i = n; i > max(n - r, r); --i) {
    if (f % i == 0)
      f /= i;
    else
      re *= i;
  }
  return (re / f);
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  fac[0] = 1;
  for (int i = 1; i <= 15; ++i) fac[i] = fac[i - 1] * i;
  cin >> b >> g >> n;
  long long ans = 0;
  for (int i = 4; i <= b; ++i) {
    if (n - i <= g && n - i >= 1) {
      ans += chose(b, i) * chose(g, n - i);
    }
  }
  cout << ans << endl;
  return 0;
}
