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 = 100;
long long dp[maxn][maxn];
void O__O() {
  for (long long i = 0; i < 100; i++) {
    for (long long j = 0; j < 100; j++) {
      if (j == 1) {
        dp[i][j] = i;
      } else if (i == 0 || j == 0) {
        dp[i][j] = 1;
      } else if (i == j) {
        dp[i][j] = 1;
      } else {
        dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j];
      }
    }
  }
}
int main() {
  O__O();
  long long n, m, t;
  cin >> n >> m >> t;
  if (t == 0) {
    dp[n + m - 5][t] = 1;
  }
  long long ans = 0;
  for (long long i = 0; i <= t - 5; i++) {
    if (4 + i <= n && 1 + (t - 5 - i) <= m)
      ans += dp[n][4 + i] * dp[m][1 + (t - 5 - i)];
  }
  cout << ans;
}
