#include <bits/stdc++.h>
using namespace std;
const int N = 210;
int n, k, m;
long long a[N];
int b[N];
int f[N][6010];
int ans = 0;
int c[N], d[N];
int main() {
  scanf("%d%d", &n, &m);
  for (int i(1); i <= (n); ++i) scanf("%lld", a + i);
  for (int i(1); i <= (n); ++i) {
    for (; a[i] % 2 == 0; a[i] /= 2) ++d[i];
    for (; a[i] % 5 == 0; a[i] /= 5) ++c[i];
  }
  for (int j(0); j <= (m); ++j)
    for (int k(0); k <= (5200); ++k) f[j][k] = -(1 << 30);
  f[0][0] = 0;
  for (int i(1); i <= (n); ++i) {
    for (int j(m); j >= (1); --j) {
      for (int k(c[i]); k <= (5200); ++k)
        f[j][k] = max(f[j][k], f[j - 1][k - c[i]] + d[i]);
    }
  }
  for (int j(0); j <= (5200); ++j) ans = max(ans, min(f[m][j], j));
  printf("%d\n", ans);
  return 0;
}
