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;
unsigned long long mod = 1000000007;
const int maxn = 100005;
unsigned long long power(unsigned long long x, unsigned long long y) {
  unsigned long long res = 1;
  x = x % mod;
  y = y % mod;
  while (y > 0) {
    if (y & 1) res = ((res % mod) * (x % mod)) % mod;
    y = y >> 1;
    x = ((x % mod) * (x % mod)) % mod;
  }
  return res % mod;
}
unsigned long long C(int n, int k) {
  unsigned long long f = 1;
  for (int i = 0; i < k; i++) f *= n - i, f /= i + 1;
  return f;
}
int main() {
  unsigned long long a, total, b;
  cin >> a >> b >> total;
  unsigned long long ans = 0;
  for (int i = 4; i <= a && i < total; i++) {
    ans += C(a, i) * C(b, total - i);
  }
  cout << ans << endl;
}
