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 oo = 0x3f3f3f3f;
const double eps = 1e-9;
long long bino[70][70];
void init() {
  for (int i = (0); i < (70); i++) {
    bino[0][i] = 1;
    bino[i][i] = 1;
    bino[i][1] = i;
    bino[i][0] = 1;
    bino[i][i - 1] = i;
  }
  for (int i = (2); i < (70); i++) {
    for (int j = (2); j < (i - 1); j++) {
      bino[i][j] = bino[i - 1][j - 1] + bino[i - 1][j];
    }
  }
}
int main() {
  int n, m, t;
  init();
  cin >> n >> m >> t;
  long long erg = 0;
  for (int i = (4); i < (t); i++) {
    erg += bino[n][i] * bino[m][t - i];
  }
  cout << erg << endl;
  return 0;
}
