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;
map<long long, long long> cnt, mark;
long long dp[35][35];
long long func(long long n, long long r) {
  if ((n == r) || (r == 0)) return 1;
  if (dp[n][r] != -1) return dp[n][r];
  return dp[n][r] = func(n - 1, r - 1) + func(n - 1, r);
}
int main() {
  long long i, j, k, l, m, n, t;
  memset(dp, -1, sizeof dp);
  cin >> n >> m >> t;
  long long ans = 0;
  for (i = 4; i <= n; i++) {
    for (j = 1; (j + i <= t) && (j <= m); j++) {
      if (j + i < t) continue;
      ans += func(n, i) * (func(m, j));
    }
  }
  cout << ans;
}
