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;
int n, m, t;
long long C[65][35], ans;
void calc() {
  for (int n = 1; n < 33; n++) {
    for (int k = 0; k < 65; k++) {
      if (k == 0 || k == n)
        C[k][n] = 1;
      else if (k > n)
        C[k][n] = 0;
      else {
        C[k][n] = C[k][n - 1] + C[k - 1][n - 1];
      }
    }
  }
}
int main() {
  calc();
  scanf("%d %d %d", &n, &m, &t);
  for (int i = 4; i < t; i++) ans += C[i][n] * C[t - i][m];
  printf("%I64d", ans);
}
