#include <bits/stdc++.h>
using namespace std;
const int maxn = 207;
int n, K;
long long a[maxn];
int sum5[maxn], sum2[maxn], dp[maxn][40 * maxn];
int main() {
  scanf("%d%d", &n, &K);
  for (int i = 1; i <= n; i++) {
    scanf("%lld", &a[i]);
    long long tmp = a[i];
    while (tmp % 5 == 0) {
      sum5[i]++;
      tmp /= 5;
    }
    tmp = a[i];
    while (tmp % 2 == 0) {
      sum2[i]++;
      tmp /= 2;
    }
  }
  memset(dp, -1, sizeof(dp));
  dp[0][0] = 0;
  for (int i = 1; i <= n; i++)
    for (int j = K; j >= 1; j--)
      for (int k = 6000; k >= 0; k--)
        if (dp[j - 1][k] != -1)
          dp[j][k + sum5[i]] = max(dp[j][k + sum5[i]], dp[j - 1][k] + sum2[i]);
  int ans = 0;
  for (int k = 0; k <= 6000; k++)
    if (dp[K][k] >= 0) ans = max(ans, min(dp[K][k], k));
  printf("%d\n", ans);
  return 0;
}
