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 dp[1000][1000];
long long ncr(long long n, long long r) {
  if (dp[n][r] != -1) return dp[n][r];
  if (dp[n][n - r] != -1) return dp[n][n - r];
  if (n == r) return 1;
  if (n < r) return 0;
  if (r == 0) return 1;
  dp[n][r] = ncr(n - 1, r) + ncr(n - 1, r - 1);
  return dp[n][r];
}
int main() {
  long long n, m, t;
  long long i, j;
  long long sum = 0;
  cin >> n >> m >> t;
  for (i = 0; i < 1000; i++)
    for (j = 0; j < 1000; j++) dp[i][j] = -1;
  for (i = 4; i <= t - 1; i++) sum += (ncr(n, i) * ncr(m, t - i));
  cout << sum << endl;
  return 0;
}
