#include <bits/stdc++.h>
using namespace std;
int n, m, s;
int f[10050][250];
int main() {
  memset(f, 0x80, sizeof(f));
  f[0][0] = 0;
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; ++i) {
    long long p;
    int x = 0, y = 0;
    scanf("%I64d", &p);
    for (; !(p % 5); p /= 5) ++x;
    for (; !(p % 2); p /= 2) ++y;
    s += x;
    for (int k = min(i, m); k >= 1; --k)
      for (int j = s; j >= x; --j) f[j][k] = max(f[j][k], f[j - x][k - 1] + y);
  }
  int ans = 0;
  for (int i = 1; i <= s; ++i) ans = max(ans, min(i, f[i][m]));
  printf("%d\n", ans);
  return 0;
}
