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[35][35];
long long nCr(long long n, long long r) {
  if (r == 1) return n;
  if (r == n || n == 1) return 1;
  if (dp[n][r] != -1) return dp[n][r];
  dp[n][r] = nCr(n - 1, r) + nCr(n - 1, r - 1);
  return dp[n][r];
}
int main() {
  long long n, m, k, p, q, r, t, n1;
  long double s = 1, s1 = 1;
  long long ans = 0, ret;
  p = 3;
  cin >> n >> m >> k;
  q = 1;
  memset(dp, -1, sizeof(dp));
  while (p <= n && q >= 1) {
    if (p + q == k && q <= m) ans += (nCr(n, p) * nCr(m, q));
    p++;
    q = k - p;
  }
  cout << ans << endl;
  return 0;
}
