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 int dp[31][31];
void compute() {
  for (int i = 1; i <= 30; i++) {
    dp[i][1] = i;
    dp[i][i] = 1;
  }
  for (int i = 1; i <= 30; i++) {
    for (int j = 2; j < i; j++) {
      dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
    }
  }
}
int main() {
  compute();
  int n, m, t;
  cin >> n >> m >> t;
  int64_t ans = 0;
  for (int i = 4; i <= n; i++) {
    if (t - i <= m && t - i >= 1) {
      ans += dp[n][i] * dp[m][t - i];
    }
  }
  cout << ans << "\n";
}
