#include <bits/stdc++.h>
using namespace std;
int n, m, allcnt, dp[205][12005], cnt2, cnt5, ans;
long long uu;
int main() {
  cin >> n >> m;
  memset(dp, 0x80, sizeof(dp));
  dp[0][0] = 0;
  for (int i = 1; i <= n; i++) {
    cin >> uu;
    cnt2 = cnt5 = 0;
    while (uu % 2 == 0) {
      cnt2++;
      uu /= 2;
    }
    while (uu % 5 == 0) {
      cnt5++;
      uu /= 5;
    }
    allcnt += cnt2;
    for (int j = min(m, i); j >= 1; j--)
      for (int k = allcnt; k >= cnt2; k--)
        dp[j][k] = max(dp[j - 1][k - cnt2] + cnt5, dp[j][k]);
  }
  for (int i = 1; i <= allcnt; i++) ans = max(ans, min(dp[m][i], i));
  cout << ans << endl;
  return 0;
}
