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;
long long binomial(int n, int r) {
  if (r >= n)
    return 1;
  else {
    if (n - r < r) r = n - r;
    int array[n + 1];
    for (int i = n - r + 1; i <= n; i++) {
      array[i] = i;
    }
    int bot[r + 1];
    for (int i = 1; i <= r; i++) {
      bot[i] = i;
    }
    int m = 0;
    while (m != 1) {
      for (int i = 2; i <= r; i++) {
        for (int j = 2; j <= r; j++) {
          for (int k = n - r + 1; k <= n; k++) {
            if (array[k] % i == 0 && bot[j] % i == 0) {
              int temp = array[k] / i;
              array[k] = temp;
              temp = bot[j] / i;
              bot[j] = temp;
            }
          }
        }
      }
      m = 1;
      for (int i = 2; i <= r; i++) {
        if (bot[i] != 1) m = 0;
      }
    }
    long long bi = 1;
    for (int i = n - r + 1; i <= n; i++) {
      bi *= array[i];
    }
    return bi;
  }
}
int main() {
  long long a, b, c;
  cin >> a;
  cin >> b;
  cin >> c;
  int dif = c - 5;
  long long count = 0;
  for (int i = 0; i <= dif; i++) {
    if (a >= 4 + i && b >= c - 4 - i)
      count += binomial(a, 4 + i) * binomial(b, c - 4 - i);
  }
  cout << count;
  return 0;
}
