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 dp[31][31];
int main() {
  int n, m, t, i;
  cin >> n >> m >> t;
  int b, g;
  for (i = 1; i <= 30; ++i) {
    dp[i][0] = 1;
    dp[i][1] = i;
  }
  int j;
  for (i = 2; i <= 30; ++i)
    for (j = 1; j <= i; ++j) {
      if (dp[i][j] == 0) dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
    }
  long long ans = 0;
  for (b = max(4, t - m); b <= min(n, t - 1); ++b) {
    g = t - b;
    ans = ans + dp[n][b] * dp[m][g];
  }
  cout << ans;
  return 0;
}
