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 MAXN = 60;
long long comb[MAXN][MAXN];
long long komb(int a, int b) {
  if (b == 0 || b == a) return comb[a][b] = comb[a][a - b] = 1;
  if (comb[a][b]) return comb[a][b];
  comb[a][b] = comb[a][a - b] = (komb(a - 1, b) + komb(a - 1, b - 1));
  return comb[a][b];
}
int main() {
  long long n, m, t;
  cin >> n >> m >> t;
  for (int i = 1; i <= 31; i++)
    for (int j = 0; j <= i; j++) komb(i, j);
  long long res = 0;
  for (int i = 4, j; i <= n; i++) {
    j = t - i;
    if (j > m) continue;
    if (j < 1) continue;
    res += comb[n][i] * comb[m][j];
  }
  cout << res << endl;
}
