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[50][50];
long long bino(long long int n, long long int r) {
  if (n == r) {
    return 1;
  }
  if (r == 1) {
    return n;
  }
  if (dp[n][r] != -1) {
    return dp[n][r];
  } else {
    dp[n][r] = bino(n - 1, r) + bino(n - 1, r - 1);
    return dp[n][r];
  }
}
int main() {
  memset(dp, -1, sizeof(dp));
  int n, m, t, i, j, k;
  long long int mum = 0, temp, kk;
  scanf("%d %d %d", &n, &m, &t);
  for (i = 4; (i <= t - 1) && i <= n; i++) {
    k = t - i;
    if (k <= m) mum += (bino(n, i) * bino(m, k));
  }
  printf("%I64d", mum);
  return 0;
}
