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 mod = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(0);
  long long n, m, t;
  cin >> n >> m >> t;
  long long answ = 0;
  for (long long i = 4; i < t; i++) {
    if (t - i <= m) {
      double temp = 1;
      for (long long j = 2; j <= i; j++) temp /= j;
      for (long long j = 2; j <= t - i; j++) temp /= j;
      for (long long j = 0; j < i; j++) temp *= (n - j);
      for (long long j = 0; j < t - i; j++) temp *= (m - j);
      answ += (long long)(temp + 0.1);
    }
  }
  cout << answ;
}
