#include <bits/stdc++.h>
using namespace std;
const int N = 201;
int dp[2][N][5001];
int n, k;
int dois[N], cinco[N];
const int inf = int(1e9);
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    long long int x;
    cin >> x;
    while (x % 2 == 0) {
      x /= 2;
      dois[i]++;
    }
    while (x % 5 == 0) {
      x /= 5;
      cinco[i]++;
    }
  }
  for (int i = 0; i < 2; i++) {
    for (int j = 0; j < N; j++) {
      for (int k = 0; k < 5001; k++) {
        dp[i][j][k] = -inf;
      }
    }
  }
  dp[1][0][0] = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j <= k; j++) {
      for (int p5 = 0; p5 < 5001; p5++) {
        int on = i & 1;
        int ant = on ^ 1;
        dp[on][j][p5] = dp[ant][j][p5];
        if (j - 1 >= 0 && p5 - cinco[i] >= 0) {
          dp[on][j][p5] =
              max(dp[on][j][p5], dp[ant][j - 1][p5 - cinco[i]] + dois[i]);
        }
      }
    }
  }
  int ans = 0;
  for (int i = 1; i < 5001; i++) {
    ans = max(ans, min(i, dp[(n - 1) & 1][k][i]));
  }
  cout << ans;
  return 0;
}
