#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long inf = (1ll << 30);
const int MX = 209;
long long dp[2][MX][MX * 30], n, k, x, f[MX], t[MX];
int main() {
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    scanf("%lld", &x);
    while (x % 2 == 0) {
      x /= 2;
      t[i]++;
    }
    while (x % 5 == 0) {
      x /= 5;
      f[i]++;
    }
  }
  long long cur = 1;
  for (int i = 0; i < 2; i++)
    for (int j = 0; j <= k; j++)
      for (int o = 0; o < MX * 30; o++) dp[i][j][o] = -inf;
  dp[0][0][0] = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j <= k; j++) {
      for (int o = 0; o < MX * 30; o++) {
        dp[cur][j][o] = dp[cur ^ 1][j][o];
        if (o - f[i] >= 0 && j - 1 >= 0)
          dp[cur][j][o] =
              max(dp[cur][j][o], dp[cur ^ 1][j - 1][o - f[i]] + t[i]);
      }
    }
    cur ^= 1;
  }
  long long ans = 0;
  for (long long i = 0; i < MX * 30; i++) {
    ans = max(ans, min(i, dp[cur ^ 1][k][i]));
  }
  cout << ans << endl;
}
