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 pascal[35][35];
int n, m, t, sisa;
long long ans;
int main() {
  pascal[1][0] = 1;
  pascal[1][1] = 1;
  for (int i = 2; i <= 30; i++) {
    for (int j = 0; j <= i; j++) {
      if (j == 0)
        pascal[i][j] = 1;
      else
        pascal[i][j] = pascal[i - 1][j] + pascal[i - 1][j - 1];
    }
  }
  scanf("%d %d %d", &n, &m, &t);
  for (int i = 4; i <= n; i++) {
    sisa = t - i;
    if (sisa < 1) break;
    if (sisa > m)
      continue;
    else
      ans += pascal[n][i] * pascal[m][sisa];
  }
  printf("%lld\n", ans);
}
