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 gn() {
  int i, j;
  i = getchar();
  while (!(((i) >= '0') && ((i) <= '9'))) i = getchar();
  j = (i - '0');
  i = getchar();
  while ((((i) >= '0') && ((i) <= '9'))) {
    j *= 10;
    j += (i - '0');
    i = getchar();
  }
  return j;
}
unsigned long long int nCr(unsigned long long int n, unsigned long long int r) {
  if (n - r < r) r = n - r;
  unsigned long long int ans = 1;
  for (unsigned long long int i = 1; i <= r; ++i) {
    ans = (ans * (n - i + 1)) / i;
  }
  return ans;
}
int main() {
  unsigned long long int n, m, t, ans = 0;
  cin >> n >> m >> t;
  for (int b = 4; b <= t - 1; ++b) {
    ans += nCr(n, b) * nCr(m, t - b);
  }
  cout << ans;
  return 0;
}
