#include <bits/stdc++.h>
using namespace std;
int readint() {
  char c;
  while (c = getchar(), (c < '0' || c > '9') && c != '-')
    ;
  bool flag = (c == '-');
  if (flag) c = getchar();
  int x = 0;
  while (c >= '0' && c <= '9') {
    x = x * 10 + c - 48;
    c = getchar();
  }
  return flag ? -x : x;
}
inline string tos(int x) {
  string s;
  while (x) s = (char)(x % 10 + '0') + s, x /= 10;
  return s;
}
int dp[2][205][5005];
long long a[205], n, k;
int main() {
  ios_base::sync_with_stdio(false);
  int i, j, l, cnt5, cnt2, ans = 0;
  cin >> n >> k;
  for (i = 1; i <= n; i++) cin >> a[i];
  memset(dp, -1, sizeof(dp));
  dp[0][0][0] = 0;
  for (i = 1; i <= n; i++) {
    cnt2 = cnt5 = 0;
    while (a[i] % 2 == 0) cnt2++, a[i] /= 2;
    while (a[i] % 5 == 0) cnt5++, a[i] /= 5;
    for (j = 0; j <= k; j++)
      for (l = 0; l <= 5000; l++) {
        dp[i & 1][j][l] = dp[(i - 1) & 1][j][l];
        if (j && l >= cnt5 && ~dp[(i - 1) & 1][j - 1][l - cnt5]) {
          dp[i & 1][j][l] =
              max(dp[i & 1][j][l], dp[(i - 1) & 1][j - 1][l - cnt5] + cnt2);
        }
      }
  }
  for (i = 0; i <= 5000; i++) {
    ans = max(ans, min(i, dp[n & 1][k][i]));
  }
  cout << ans << endl;
  return 0;
}
