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 int dp[100][100];
int main() {
  dp[0][0] = 0;
  dp[0][1] = 1;
  dp[1][1] = 1;
  for (int i = 0; i <= 30; i++) {
    for (int j = 0; j <= 30; j++) {
      if (j == 0 || i == j)
        dp[i][j] = 1;
      else
        dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
    }
  }
  long long int n, m, t, sum = 0;
  cin >> n >> m >> t;
  for (int i = 4; i < t; i++) {
    int g = t - i;
    sum += dp[n][i] * dp[m][g];
  }
  cout << sum;
}
