#include <bits/stdc++.h>
using namespace std;
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << "\n";
  err(++it, args...);
}
const double PI = acos(-1);
const double eps = (1e-9);
const long long int INF = (1e18);
const int M = (1e9) + 7;
const int N = 203;
const int K = 5250;
int dp[N][K];
int ar[N][K];
void solve() {
  int n, r, i, j, k, a, b;
  scanf("%d%d", &n, &r);
  vector<pair<int, int> > vp;
  long long int x;
  for (i = 0; i < n; ++i) {
    cin >> x;
    a = 0, b = 0;
    while (x % 2 == 0) x /= 2, a++;
    while (x % 5 == 0) x /= 5, b++;
    vp.emplace_back(a, b);
  }
  for (i = 0; i < N; ++i) {
    for (j = 0; j < K; ++j) dp[i][j] = -1, ar[i][j] = -1;
  }
  dp[0][0] = 0, ar[0][0] = 0;
  for (i = 0; i < n; ++i) {
    tie(a, b) = vp[i];
    for (j = 0; j < i + 1; ++j) {
      for (k = 0; k < K - b; ++k) {
        if (dp[j][k] >= 0)
          ar[j + 1][k + b] = max(ar[j + 1][k + b], dp[j][k] + a);
      }
    }
    for (j = 0; j < N; ++j) {
      for (k = 0; k < K; ++k) dp[j][k] = max(dp[j][k], ar[j][k]);
    }
  }
  k = 0;
  for (j = 0; j < K; ++j) {
    if (dp[r][j] >= 0) k = max(k, min(j, dp[r][j]));
  }
  printf("%d\n", k);
}
int main() {
  int t;
  t = 1;
  while (t--) solve();
}
