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 mod = 1e9 + 7;
int dp[31][31];
long long bin(long long n, long long t) {
  if (dp[n][t] != 0) return dp[n][t];
  if (t == 0 || t == n)
    dp[n][t] = 1;
  else
    dp[n][t] = bin(n - 1, t - 1) + bin(n - 1, t);
  return dp[n][t];
}
int main() {
  long long n, m, t;
  cin >> n >> m >> t;
  long long ans = 0;
  for (int x = 4; x <= n; ++x) {
    for (int y = 1; y <= m; ++y) {
      if (x + y == t) {
        ans += (bin(n, x) * bin(m, y));
      }
    }
  }
  cout << ans;
}
