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;
int readint() {
  int t = 0;
  char c, ch;
  ch = getchar();
  if (ch == '-')
    c = getchar();
  else
    c = ch;
  while (c < '0' || c > '9') c = getchar();
  while (c >= '0' && c <= '9') {
    t = (t << 3) + (t << 1) + c - '0';
    c = getchar();
  }
  if (ch == '-')
    return -t;
  else
    return t;
}
unsigned long long choose(int n, int m) {
  int i;
  if (n < m) return 0;
  m = min(m, n - m);
  unsigned long long q = 1;
  for (i = 0; i < m; i++) {
    q = q * (n - i) / (i + 1);
  }
  return q;
}
int main() {
  int i, j, k, t, n, m, x, y, b, g;
  cin >> b >> g >> t;
  unsigned long long ans = 0, p = 1;
  cout << choose(b + g, t) - choose(b, t) - choose(g, t) -
              choose(g, t - 1) * choose(b, 1) -
              choose(g, t - 2) * choose(b, 2) - choose(g, t - 3) * choose(b, 3)
       << endl;
  return 0;
}
