#include <bits/stdc++.h>
using namespace std;
long long a[210], b[210];
long long dp[210][10010];
long long n, m, x, ans;
void djj_lxy() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  memset(dp, -1, sizeof dp);
  dp[0][0] = 0;
  cin >> n >> m;
  for (register long long i = 1; i <= n; i++) {
    cin >> x;
    while (x % 2 == 0) x /= 2, a[i]++;
    while (x % 5 == 0) x /= 5, b[i]++;
  }
  for (register long long i = 1; i <= n; i++)
    for (register long long j = m; j >= 0; j--)
      for (register long long k = 10000; k >= 0; k--)
        if (j >= 1 && k >= b[i] && dp[j - 1][k - b[i]] != -1)
          dp[j][k] = max(dp[j][k], dp[j - 1][k - b[i]] + a[i]);
  for (register long long i = 0; i <= 10000; i++)
    ans = max(ans, min(i, dp[m][i]));
  cout << ans;
}
signed main() { djj_lxy(); }
