#include <bits/stdc++.h>
using namespace std;
const int N = 200 + 5, LG = 40, inf = 1e9;
pair<int, int> dp[2][N][LG * N];
int n, m, a[N], b[N];
pair<int, int> mx(pair<int, int> x, pair<int, int> y) {
  if (x.first == y.first) return ((x.second > y.second) ? x : y);
  return ((x.first > y.first) ? x : y);
}
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> m;
  for (int i = 0; i < n; i++) {
    long long x;
    cin >> x;
    while (x % 2 == 0) a[i]++, x /= 2;
    while (x % 5 == 0) b[i]++, x /= 5;
  }
  for (int i = 0; i <= 1; i++)
    for (int j = 0; j <= m; j++)
      for (int k = 0; k < N * LG; k++) dp[i][j][k] = {-inf, -inf};
  dp[0][0][0] = {0, 0};
  for (int i = 0; i < n; i++) {
    for (int j = 0; j <= min(i + 1, m); j++) {
      for (int k = 0; k <= (i + 1) * LG; k++) {
        dp[(i + 1) & 1][j][k] = dp[i & 1][j][k];
        if (j && k >= b[i]) {
          int mn = min(k, dp[i & 1][j - 1][k - b[i]].second + a[i]);
          dp[(i + 1) & 1][j][k] =
              mx(dp[(i + 1) & 1][j][k],
                 make_pair(mn, dp[i & 1][j - 1][k - b[i]].second + a[i]));
        }
      }
    }
  }
  pair<int, int> ans = {0, 0};
  for (int i = 0; i <= n * LG; i++) ans = mx(ans, dp[n & 1][m][i]);
  cout << ans.first << "\n";
}
