#include <bits/stdc++.h>
using namespace std;
int dp[2][202][28 * 204];
vector<pair<long long int, long long int> > A(202);
int n, k;
int main() {
  for (int i = 0; i < 2; i++)
    for (int j = 0; j < 202; j++)
      for (int l = 0; l < 202 * 28; l++) dp[i][j][l] = -10000000;
  cin >> n >> k;
  for (int i = 1; i <= n; i++) {
    long long int temp;
    cin >> temp;
    int two = 0, five = 0;
    while (temp % 2 == 0) temp = temp / 2, two++;
    while (temp % 5 == 0) temp = temp / 5, five++;
    A[i].first = two;
    A[i].second = five;
  }
  dp[0][0][0] = 0;
  for (int i = 1; i <= n; i++) {
    int two = A[i].first;
    int five = A[i].second;
    for (int j = min(k, i); j >= 0; j--) {
      for (int l = 0; l < 202 * 28; l++) {
        if (l >= five && j > 0)
          dp[i & 1][j][l] =
              max(dp[i & 1][j][l], dp[~i & 1][j - 1][l - five] + two);
        dp[i & 1][j][l] = max(dp[i & 1][j][l], dp[~i & 1][j][l]);
      }
    }
  }
  int ans = 0;
  for (int i = 0; i < 202 * 28; i++) {
    ans = max(ans, min(i, dp[n & 1][k][i]));
  }
  cout << ans;
  return 0;
}
