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;
const double eps = 1e-6;
const double pi = acos(-1.0);
const int mod = 1e6 + 3;
const int INF = 0x3f3f3f3f;
long long c[35][35];
void init() {
  memset(c, 0, sizeof(c));
  c[0][0] = c[1][0] = c[1][1] = 1;
  for (int i = 2; i <= 30; i++) {
    c[i][0] = c[i][i] = 1;
    for (int j = 1; j < i; j++) c[i][j] = c[i - 1][j] + c[i - 1][j - 1];
  }
}
int main() {
  int n, m, t;
  init();
  cin >> n >> m >> t;
  long long ans = 0;
  for (int i = 4; i <= t - 1; i++) {
    if (t - i <= m && i <= n) ans += c[n][i] * c[m][t - i];
  }
  cout << ans << endl;
  return 0;
}
