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[35][35];
long long int ncr(long long int n, long long int r) {
  if (r == 1) return n;
  if (n == r) return 1;
  if (dp[n][r] != -1) {
    return dp[n][r];
  }
  return dp[n][r] = ncr(n - 1, r) + ncr(n - 1, r - 1);
}
int main() {
  memset(dp, -1, sizeof dp);
  long long int n, m, k;
  scanf("%lld%lld%lld", &n, &m, &k);
  long long int ans = 0;
  for (long long int i = 4; i <= n; i++) {
    long long int b = i;
    long long int g = k - i;
    if (g >= 1 && g <= m) {
      long long int now = ncr(n, b) * ncr(m, g);
      ans += now;
    }
  }
  printf("%lld\n", ans);
  return 0;
}
