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> m1;
long long dp[1000][1000];
bool used[100001];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  memset(dp, 0, sizeof(dp));
  for (long long i = 1; i <= 30; i++) {
    for (long long j = 0; j <= i; j++) {
      if (j == 0 || j == i) {
        dp[i][j] = 1;
      } else {
        dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
      }
    }
  }
  long long ans = 0;
  long long n, m, t;
  cin >> n >> m >> t;
  for (long long j = 4; j <= n; j++) {
    long long k = t - j;
    if (k >= 1 && k <= m) {
      ans += dp[n][j] * dp[m][k];
    }
  }
  cout << ans;
  return 0;
}
