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;
inline long long gcd(long long a, long long b) {
  return b == 0 ? a : gcd(b, a % b);
}
inline long long lcm(long long a, long long b) { return a * (b / gcd(a, b)); }
long long c[65][65];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n, m, t, ans = 0;
  cin >> n >> m >> t;
  c[0][0] = 1;
  for (int(i) = (1); (i) <= (64); (i)++) {
    c[i][0] = 1;
    c[0][i] = 0;
  }
  for (int(i) = (1); (i) <= (64); (i)++)
    for (int(j) = (1); (j) <= (64); (j)++)
      c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
  for (long long i = 4; i < t; i++) ans += c[n][i] * c[m][t - i];
  cout << ans;
  return 0;
}
