#include <bits/stdc++.h>
using namespace std;
const int mxn = 201, mxb = 60;
int dp[mxn * mxb][mxn];
int main() {
  int n, k;
  scanf("%d%d", &n, &k);
  memset(dp, -1, sizeof(dp));
  dp[0][0] = 0;
  for (int l = 1, a, b; l <= n; ++l) {
    long long x;
    scanf("%lld", &x);
    for (a = 0; x % 2 == 0; x /= 2, ++a)
      ;
    for (b = 0; x % 5 == 0; x /= 5, ++b)
      ;
    for (int j = k - 1; j >= 0; --j) {
      for (int i = l * 60; i >= a; --i)
        if (dp[i - a][j] != -1)
          dp[i][j + 1] = max(dp[i][j + 1], b + dp[i - a][j]);
    }
  }
  int ret = 0;
  for (int i = 0; i <= 60 * n; ++i) ret = max(ret, min(i, dp[i][k]));
  printf("%d\n", ret);
}
