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;
const long long N = 105;
long long cache[N][N];
long long n, m, t;
long long nCr(long long n, long long r) {
  if (r == 0) return 1;
  if (n == r) return 1;
  long long &ans = cache[n][r];
  if (ans != -1) return ans;
  ans = nCr(n - 1, r - 1) + nCr(n - 1, r);
  return ans;
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  memset(cache, -1, sizeof(cache));
  cin >> n >> m >> t;
  long long ans = 0;
  for (long long i = 4; i <= min(n, t); i++) {
    if (t - i <= 0) break;
    if (t - i > m) continue;
    ans += nCr(n, i) * nCr(m, t - i);
  }
  cout << ans;
  return 0;
}
