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;
int dir4[4][2] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
int dir8[8][2] = {{-1, 0}, {1, 0},  {0, 1}, {0, -1},
                  {-1, 1}, {1, -1}, {1, 1}, {-1, -1}};
int dir8h[8][2] = {{2, 1}, {-2, -1}, {-1, 2}, {1, -2},
                   {1, 2}, {-2, 1},  {2, -1}, {-1, -2}};
long double eps = 1e-7;
const int N = 1e6 + 100;
long long c(long long n, long long k) {
  long long res = 1;
  k = min(k, n - k);
  for (long long i = 1; i <= k; i++) res *= (n - i + 1), res /= i;
  return res;
}
int main() {
  ios_base::sync_with_stdio(false);
  long long n, m, t, ans = 0;
  cin >> n >> m >> t;
  for (long long i = 4; i <= n; i++)
    if (t - i >= 1 && m >= t - i) ans += c(n, i) * c(m, t - i);
  cout << ans;
}
