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;
long long n, m, t;
long long dp[35][35];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  for (int i = 0; i <= 30; i++) {
    dp[i][0] = 1;
  }
  for (int i = 0; i <= 30; i++) {
    dp[i][i] = 1;
  }
  for (int i = 0; i <= 30; i++) {
    for (int j = 0; j <= i; j++) {
      if (i != 0 || j != 0 || i != j) {
        dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j];
      }
    }
  }
  cin >> n >> m >> t;
  vector<pair<long long, long long>> kombinasi;
  for (long long i = 4; i <= n; i++) {
    for (long long j = 1; j <= m; j++) {
      if (i + j == t) {
        kombinasi.push_back(make_pair(i, j));
      }
    }
  }
  long long res = 0;
  for (auto x : kombinasi) {
    long long coba = (dp[n][x.first] * dp[m][x.second]);
    res += coba;
  }
  cout << res << '\n';
  return 0;
}
