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 comb[31][61];
void init() {
  memset(comb, 0, sizeof(comb));
  for (int i = 0; i <= 30; i++) {
    comb[i][0] = 1;
    for (int j = 1; j <= i; j++) {
      comb[i][j] = comb[i - 1][j] + comb[i - 1][j - 1];
    }
  }
}
long long solve(int t, int n, int m) {
  long long ans = 0;
  for (int girls = 1; t - girls >= 4; girls++) {
    int boys = t - girls;
    ans += comb[m][girls] * comb[n][boys];
  }
  return ans;
}
int main() {
  init();
  int t, n, m;
  scanf("%d %d %d", &n, &m, &t);
  long long ans = solve(t, n, m);
  printf("%I64d\n", ans);
}
