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 i, j, k, l, x, y, z, m, n, ans, p, q, t;
long long dp[40][40];
long long nCr(long long i, long long j) {
  if (j == 0 || j == i) return 1;
  if (j == 1) return i;
  if (dp[i][j] != -1) return dp[i][j];
  dp[i][j] = nCr(i - 1, j) + nCr(i - 1, j - 1);
  return dp[i][j];
}
int main() {
  memset(dp, -1, sizeof(dp));
  cin >> n >> m >> t;
  for (i = 4; i <= n; i++) {
    j = t - i;
    if (j < 1) break;
    if (j > m) continue;
    ans += nCr(n, i) * nCr(m, j);
  }
  printf("%I64d", ans);
  return 0;
}
