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>
long long m, n, t;
int min(int x, int y) { return x < y ? x : y; }
int max(int x, int y) { return x > y ? x : y; }
long long calc(int x, int y) {
  if (x - y > y) y = x - y;
  int i, j;
  long long s = 1;
  for (i = 0, j = 1; i < y; ++i) {
    s *= (x - i);
    for (; j <= y && s % j == 0; ++j) s /= j;
  }
  return s;
}
void work() {
  int k;
  long long ans = 0;
  for (k = max(1, t - n); k <= min(t - 4, m); k++) {
    ans += calc(m, k) * calc(n, t - k);
  }
  printf("%I64d\n", ans);
}
int main() {
  while (scanf("%I64d%I64d%I64d", &n, &m, &t) != EOF) {
    work();
  }
  return 0;
}
