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 fact(int n, int k) {
  long long sum = 1;
  for (int i = 1; i <= k; i++) {
    sum = sum * n;
    sum = sum / i;
    n--;
  }
  return sum;
}
int main() {
  int a, b, c;
  cin >> a >> b >> c;
  long long sum = 0;
  int k = c - 4;
  if (b == 1 && a + b == c) {
    cout << b << endl;
    return 0;
  } else if (a <= b && a + b == c) {
    cout << 1 << endl;
    return 0;
  } else {
    for (int i = 4, j = k; i < 4 + k, j >= 1; i++, j--) {
      sum = sum + ((fact(a, i) * (fact(b, j))));
    }
    cout << sum << endl;
  }
}
