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[50][50] = {};
long long c(long long n, long long k);
int main() {
  for (long long i = 0; i < 50; i++) {
    for (long long j = 0; j < 50; j++) dp[i][j] = -1;
  }
  long long n, m, t, ans = 0;
  scanf("%I64d %I64d %I64d", &n, &m, &t);
  for (long long k = 4; k <= min(n, t - 1); k++) {
    if (t - k <= m) ans += c(n, k) * c(m, t - k);
  }
  printf("%I64d", ans);
}
long long c(long long n, long long k) {
  if (k == n || k == 0) return 1;
  if (dp[n][k] != -1) return dp[n][k];
  return dp[n][k] = c(n - 1, k) + c(n - 1, k - 1);
}
