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 double pi = 3.14159265358979323;
long long int n, k, m, tc, ans = 0, count = 0, mymax = -1e18, mymin = 1e18, x,
                           y, q;
string final_ans = "";
string s = "";
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
  for (int i = 0; i < v.size(); i += 1) os << v[i] << " ";
  os << '\n';
  return os;
}
long long int choose[1000][1000];
void generate_choose_dp(long long int mod) {
  for (int i = 0; i < 1000; i += 1) {
    choose[i][0] = 1;
    choose[i][i] = 1;
  }
  for (int i = 1; i < 1000; i++) {
    for (int j = 1; j <= i; j++) {
      choose[i][j] = choose[i - 1][j - 1] + choose[i - 1][j];
      choose[i][j] %= mod;
    }
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int t;
  cin >> n >> m >> t;
  generate_choose_dp(2e18);
  ans = 0;
  for (long long int boys = 4; boys <= min(n, t - 1); boys++) {
    long long int girls = t - boys;
    ans += choose[n][boys] * choose[m][girls];
  }
  cout << ans;
}
