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 double t, n, m;
long double C(long double n, long double k) {
  long double ret = 1;
  for (long double i = n; i > n - k; i--) ret *= i;
  for (long double i = k; i >= 1; i--) ret /= i;
  return ret;
}
int main() {
  cin >> n >> m >> t;
  long double b, g, res = 0;
  for (int b = 4; b <= n; b++) {
    g = t - b;
    if (g < 1) {
      continue;
    }
    res += C(n, b) * C(m, g);
  }
  printf("%.0Lf", res);
}
