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>
int min(int a, int b) {
  if (a > b) return a;
  return b;
}
int max(int a, int b) {
  if (a > b) return b;
  return a;
}
long long int c(int a, int b) {
  int i;
  double x = 1;
  for (i = 2; i <= b; i++) {
    x *= i;
    if (i <= min(a, b - a)) x /= i;
  }
  for (i = 1; i <= b - min(a, b - a); i++) x /= i;
  return x;
}
int main() {
  long long int s = 0;
  int n, m, t, i;
  scanf("%d%d%d", &n, &m, &t);
  for (i = min(t - m, 4); i <= max(t - 1, n); i++) {
    s += (c(i, n) * c(t - i, m));
  }
  printf("%I64d", s);
}
