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 INF = 1e9;
const long long N = 1e3 + 1;
const long long mod = 1e7 + 9;
const long double eps = 1E-7;
long long ans;
long long n, m, t;
long long comb(long long a, long long b) {
  long long res = 1;
  long long x = min(a, b - a);
  long long y = max(a, b - a);
  for (; b > y; b--) {
    res *= b;
    while (res % x == 0 and x != 1) res /= x, x = x - 1;
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n >> m >> t;
  for (long long i = 4; i <= n; i++) {
    for (long long j = 1; j <= m; j++) {
      if (i + j == t) ans += comb(i, n) * comb(j, m);
    }
  }
  cout << ans << endl;
}
