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 n, m, t;
long long c[32][32];
int main() {
  memset(c, 0, sizeof(c));
  for (int i = 0; i <= 30; ++i) {
    c[0][i] = c[i][i] = 1;
    for (int j = 1; j < i; ++j) c[j][i] = c[j - 1][i - 1] + c[j][i - 1];
  }
  cin >> n >> m >> t;
  long long res = 0;
  for (int i = 4; i <= t - 1; ++i)
    if (i <= n && t - i <= m) res += c[i][n] * c[t - i][m];
  cout << res << endl;
  return 0;
}
