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>
int diri[] = {-1, 0, 1, 0, -1, 1, 1, -1};
int dirj[] = {0, 1, 0, -1, 1, 1, -1, -1};
int compare(double d1, double d2) {
  if (fabs(d1 - d2) < 1e-9) return 0;
  if (d1 < d2) return -1;
  return 1;
}
using namespace std;
long long sv[31][31];
int n, m;
long long dp(int ind, int cnt) {
  if (ind > m) return 0;
  if (cnt == n) return 1;
  if (sv[ind][cnt] != -1) return sv[ind][cnt];
  return sv[ind][cnt] = dp(ind + 1, cnt) + dp(ind + 1, cnt + 1);
}
int main() {
  int t, g, b;
  cin >> b >> g >> t;
  long long ans = 0;
  for (int i = 4; i <= t - 1; ++i) {
    memset(sv, -1, sizeof(sv));
    m = b, n = i;
    long long a = dp(0, 0);
    memset(sv, -1, sizeof(sv));
    m = g, n = t - i;
    long long b = dp(0, 0);
    ans += a * b;
  }
  cout << ans << endl;
  return 0;
}
