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 ff(int a, int b) {
  int c = b - a;
  a = min(a, c);
  long long res = 1;
  for (int i = 1; i <= a; i++) {
    res *= (b - i + 1);
    res /= i;
  }
  return res;
}
int main() {
  int n, m, t, Y;
  scanf("%d%d%d", &n, &m, &t);
  long long sum = 0;
  for (int i = 4; i <= n; i++) {
    Y = t - i;
    if (Y < 1 || Y > m) continue;
    sum += ff(i, n) * ff(Y, m);
  }
  cout << sum << endl;
  return 0;
}
