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 int MAXN = 30;
long long C[MAXN + 1][MAXN + 1];
int main() {
  int n, m, k, t, b, lim;
  long long ans = 0LL;
  for (n = 0; n <= MAXN; ++n) {
    C[n][0] = C[n][n] = 1LL;
    for (k = 1; k < n; ++k) C[n][k] = C[n - 1][k - 1] + C[n - 1][k];
  }
  scanf("%d%d%d", &n, &m, &t);
  lim = min(t - 1, n);
  for (b = max(4, t - m); b <= lim; ++b) ans += C[n][b] * C[m][t - b];
  printf("%I64d\n", ans);
  return 0;
}
