#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 10;
const int MOD = 1e9 + 7;
int dp[210][5200];
int e2[210], e5[210];
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 1; i <= n; ++i) {
    long long e;
    cin >> e;
    for (long long x = e; x % 2 == 0 and x > 0; x /= 2) e2[i]++;
    for (long long x = e; x % 5 == 0 and x > 0; x /= 5) e5[i]++;
  }
  for (int i = 0; i < 210; ++i) fill(dp[i], dp[i] + 5200, -1e9);
  dp[0][0] = 0;
  int max_e5 = 0;
  for (int i = 1; i <= n; ++i) {
    max_e5 += e5[i];
    for (int j = i; j >= 1; --j) {
      for (int ex5 = max_e5; ex5 >= e5[i]; --ex5) {
        dp[j][ex5] = max(dp[j - 1][ex5 - e5[i]] + e2[i], dp[j][ex5]);
      }
    }
  }
  int ans = 0;
  for (int ex5 = 0; ex5 <= max_e5; ++ex5) {
    ans = max(min(dp[k][ex5], ex5), ans);
  }
  cout << ans << endl;
  return 0;
}
