#include <bits/stdc++.h>
using namespace std;
const int inf = 2147483647;
int two[205], five[205];
int dp[2][205][5200];
int possible[2][205][5200];
long long int a[205];
int main() {
  int n, K;
  scanf("%d%d", &n, &K);
  for (int i = 1; i <= n; i++) {
    scanf("%lld", a + i);
    while (a[i] % 2 == 0) a[i] /= 2, two[i]++;
    while (a[i] % 5 == 0) a[i] /= 5, five[i]++;
  }
  dp[0][0][0] = 0;
  possible[0][0][0] = 1;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < 5200; j++) dp[i & 1][0][j] = dp[i & 1][i + 1][j] = 0;
    possible[i & 1][0][0] = 1;
    for (int j = 1; j <= i; j++) {
      for (int k = 0; k < 5200; k++) {
        dp[i & 1][j][k] = dp[1 - i & 1][j][k];
        possible[i & 1][j][k] = possible[1 - i & 1][j][k];
        if (possible[1 - i & 1][j - 1][k - five[i]]) possible[i & 1][j][k] = 1;
        if (k >= five[i] && possible[1 - i & 1][j - 1][k - five[i]]) {
          dp[i & 1][j][k] =
              max(dp[i & 1][j][k], dp[1 - i & 1][j - 1][k - five[i]] + two[i]);
        }
      }
    }
  }
  int ans = 0;
  for (int i = 0; i < 5200; i++) {
    if (possible[n % 2][K][i]) ans = max(ans, min(i, dp[n % 2][K][i]));
  }
  printf("%d\n", ans);
}
