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>
long long chooses[31][31];
using namespace std;
long long factorial(long long a) {
  long long answer = 1;
  for (long long i = 1; i <= a; i++) answer *= i;
  return answer;
}
void ch(int i, int j) {
  if (j == 0 or j == i) {
    chooses[i][j] = 1;
  } else
    chooses[i][j] = chooses[i - 1][j - 1] + chooses[i - 1][j];
}
void doChooses() {
  for (int i = 0; i < 31; i++)
    for (int j = 0; j <= i; j++) ch(i, j);
}
int main() {
  doChooses();
  long long n, m, t;
  cin >> n >> m >> t;
  long long answer = 0;
  long long temp = 0;
  temp = max(t - n, 1ll);
  for (long long girls = temp;
       (girls <= t - 4) and (girls <= m) and (t - girls <= n); girls++) {
    long long currWays = chooses[m][girls] * chooses[n][t - girls];
    answer += currWays;
  }
  cout << answer << endl;
  return 0;
}
