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 MAX = 1000000000;
long long MOD = 1000000007;
long long ncr(long long n, long long m) {
  long long a = 1, k = 1;
  for (long long i = n; i > n - m; i--) {
    a *= i;
    if (k <= m) a /= k;
    k++;
  }
  return a;
}
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  long long test = 1;
  while (test--) {
    long long n;
    cin >> n;
    long long m;
    cin >> m;
    long long t;
    cin >> t;
    ;
    long long ans = 0;
    for (long long i = (4); i < (t); i++) {
      if (i <= n && t - i <= m) {
        ans += ncr(n, i) * ncr(m, t - i);
      }
    }
    cout << ans;
  }
}
