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;
const long long mod7 = 1000000007, mod = 1000000000, OO = 0x3f3f3f3f,
                NegOO = -1 * OO;
double Pi = acos(-1);
const double long rad = Pi / 180.0;
long long GCD(long long a, long long b) { return (b == 0) ? a : GCD(b, a % b); }
long long LCM(long long a, long long b) { return a * b / GCD(a, b); }
int solve(int i, int used) { return 0; }
long long dp_ncr[100][100];
long long nCr(long long n, long long m) {
  if (m == 0) return 1;
  return n * nCr(n - 1, m - 1) / m;
}
int main() {
  long long n, m, t, ans = 0;
  cin >> n >> m >> t;
  for (int i = (4); i < (t); i++) {
    ans += nCr(n, i) * nCr(m, t - i);
  }
  cout << ans;
}
