#include <bits/stdc++.h>
using namespace std;
int dp[2][202][202 * 28];
int cal(long long n, long long m) {
  int ret = 0;
  while (n % m == 0) {
    n /= m;
    ret++;
  }
  return ret;
}
int main() {
  int n, k, i, j, l, five, two, m;
  long long x;
  scanf("%d", &n);
  scanf("%d", &k);
  m = 28 * n;
  for (i = 0; i <= n; ++i) {
    for (j = 0; j <= m; ++j) {
      dp[0][i][j] = -1000000;
      dp[1][i][j] = -1000000;
    }
  }
  for (j = 0; j <= k; j++) {
    dp[0][j][0] = 0;
    dp[1][j][0] = 0;
  }
  for (i = 1; i <= n; ++i) {
    scanf("%lld", &x);
    five = cal(x, 5);
    two = cal(x, 2);
    for (j = 1; j <= k; ++j) {
      for (l = 0; l <= m; ++l) {
        if (l - five >= 0) {
          dp[i & 1][j][l] = max(dp[(i - 1) & 1][j - 1][l - five] + two,
                                dp[(i - 1) & 1][j][l]);
        } else {
          dp[i & 1][j][l] = dp[(i - 1) & 1][j][l];
        }
      }
    }
  }
  int ans = 0;
  for (i = 0; i <= m; ++i) {
    ans = max(ans, min(dp[n & 1][k][i], i));
  }
  printf("%d\n", ans);
}
