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 funk(long long x, long long y) {
  bool used[10000];
  long long res = 1;
  for (long long i = 1; i <= 100; i++) used[i] = 0;
  for (long long i = x + 1; i <= y; i++) {
    res *= i;
    for (long long j = 2; j <= y - x; j++) {
      if (!used[j] && res % j == 0) {
        res /= j;
        used[j] = 1;
      }
    }
  }
  return res;
}
int main() {
  long long n, m, t, i, j;
  cin >> n >> m >> t;
  long long s = 0;
  for (i = 4; i < t && i <= n; i++) {
    if (t - i <= m) {
      s += (funk(i, n) * funk(t - i, m));
    }
  }
  cout << s << "\n";
}
