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;
const int maxn = 32;
long long com[maxn][maxn];
void init() {
  for (int i = 0; i < maxn; i++) com[i][0] = com[i][i] = 1;
  for (int i = 1; i < maxn; i++)
    for (int j = 1; j < i; j++) com[i][j] = com[i - 1][j - 1] + com[i - 1][j];
}
int main() {
  init();
  cin >> n >> m >> t;
  int dn = max(4, t - m), up = min(n, t - 1);
  long long res = 0;
  for (int i = dn; i <= up; i++) res += com[n][i] * com[m][t - i];
  cout << res << endl;
}
