#include <bits/stdc++.h>
using namespace std;
const long long MXN = 205;
const long long MX5 = MXN * 27;
long long n, k;
long long dp[MXN][MX5];
int main() {
  memset(dp, ~0x3f, sizeof(dp));
  dp[0][0] = 0;
  scanf("%lld%lld", &n, &k);
  for (long long i = 1; i <= n; i++) {
    long long tmp, c2 = 0, c5 = 0;
    scanf("%lld", &tmp);
    while (!(tmp & 1)) {
      tmp >>= 1;
      c2++;
    }
    while (!(tmp % 5)) {
      tmp /= 5;
      c5++;
    }
    for (long long j = min(i, k); j; j--)
      for (long long l = MX5 - 1; l >= c5; l--)
        dp[j][l] = max(dp[j][l], dp[j - 1][l - c5] + c2);
  }
  long long ans = 0;
  for (long long i = 1; i < MX5; i++) ans = max(ans, min(i, dp[k][i]));
  printf("%lld", ans);
  return 0;
}
