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 = (int)1e9;
const int maxint = 0x7f;
unsigned long long cnk(unsigned long long nn, unsigned long long kk) {
  const int maxn = 60;
  unsigned long long C[maxn + 1][maxn + 1];
  for (int n = 0; n <= maxn; ++n) {
    C[n][0] = C[n][n] = 1;
    for (int k = 1; k < n; ++k) C[n][k] = C[n - 1][k - 1] + C[n - 1][k];
  }
  return C[nn][kk];
}
int main() {
  unsigned long long n, m, t;
  unsigned long long ans = 0;
  cin >> n >> m >> t;
  for (int i = 4; i < t; ++i) {
    ans += cnk(n, i) * cnk(m, t - i);
  }
  cout << ans;
  cout << '\n';
  return 0;
}
