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 ans;
inline long long com(int n, int m) {
  long long res = 1;
  for (register int i = m - n + 1; i <= m; ++i) res = res * i / (i - m + n);
  return res;
}
int main() {
  int n, m, t;
  scanf("%d%d%d", &n, &m, &t);
  for (register int i = max(1, t - n); i <= min(t - 4, m); ++i)
    ans += com(i, m) * com(t - i, n);
  printf("%I64d\n", ans);
  return 0;
}
