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 C[100][100];
void binomialCoeff(long long n, long long k) {
  long long i, j;
  for (i = 0; i <= n; i++) {
    for (j = 0; j <= min(i, k); j++) {
      if (j == 0 || j == i)
        C[i][j] = 1;
      else
        C[i][j] = C[i - 1][j - 1] + C[i - 1][j];
    }
  }
}
int main() {
  long long n, m, t;
  scanf("%lld", &n);
  scanf("%lld", &m);
  scanf("%lld", &t);
  long long ans = 0;
  binomialCoeff(90, 90);
  for (long long i = 4; i <= t - 1 && i <= n; i++) {
    if (t - i <= m) {
      ans += C[n][i] * C[m][t - i];
    }
  }
  printf("%lld\n", ans);
  return 0;
}
