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;
void set_val(vector<long long>& v, long long val) {
  for (long long i = 0; i < v.size(); i++) v[i] = val;
}
long long mod = pow(10, 9) + 7;
long long modulo = 998244353;
double pi = acos(-1.0);
long long i_mov[8] = {-1, 0, 1, 1, 1, 0, -1, -1};
long long j_mov[8] = {1, 1, 1, 0, -1, -1, -1, 0};
long long power(long long a, long long n, long long m = mod) {
  if (n == 0) return 1;
  long long temp = power(a, n / 2, m);
  if (n % 2 == 0) return (temp * temp) % m;
  return (((temp * temp) % m) * a) % m;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cout << fixed;
  cout << setprecision(10);
  long long n, m, t;
  cin >> n >> m >> t;
  vector<long long> a(n + 1, 1), b(m + 1, 1);
  for (long long i = 1; i < n + 1; i++) a[i] = (a[i - 1] * (n - i + 1)) / i;
  for (long long i = 1; i < m + 1; i++) b[i] = (b[i - 1] * (m - i + 1)) / i;
  long long ans = 0;
  for (int i = 4; i <= min(n, t - 1); i++) {
    if (t - i <= m) ans += a[i] * b[t - i];
  }
  cout << ans;
}
