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 res;
long long fact(long long n) {
  if (n <= 1) return 1;
  return fact(n - 1) * n;
}
long long C(long long n, long long r) {
  if (r > n) return 0;
  if (r * 2 > n) r = n - r;
  if (r == 0) return 1;
  long long ret = n;
  for (int i = 2; i <= r; ++i) {
    ret *= (n - i + 1);
    ret /= i;
  }
  return ret;
}
void comp(long long b, long long g, long long tot) {
  for (int i = 4; i <= tot; i++) {
    long long fromB = C(b, i);
    long long fromG = C(g, tot - i);
    if (tot - i < 1) continue;
    res += fromB * fromG;
  }
}
int main() {
  long long b, g, tot;
  cin >> b >> g >> tot;
  comp(b, g, tot);
  cout << res << '\n';
  return 0;
}
