/*
CodeForces 837D - Round Subset [ DP ] | Educational Codeforces Round 26
题意：
选k个数相乘让末尾0最多
分析：
第i个数字有a[i]个2, b[i] 个5
以其中一维作体积另一维作价值01背包即可
*/
#include <bits/stdc++.h>
using namespace std;
int dp[205][20005];
int get2(long long x)
{
int s = 0;
while (x % 2 == 0) s++, x /= 2;
return s;
}
int get5(long long x)
{
int s = 0;
while (x % 5 == 0) s++, x /= 5;
return s;
}
int n, k;
int main()
{
scanf("%d%d", &n, &k);
memset(dp, -1, sizeof(dp));
dp[0][0] = 0;
for (int i = 1; i <= n; i++)
{
long long x; scanf("%lld", &x);
int a = get2(x);
int b = get5(x);
for (int j = k; j >= 1; j--)
for (int p = a; p <= 20000; p++)
if (dp[j-1][p-a] != -1)
dp[j][p] = max(dp[j][p], dp[j-1][p-a] + b);
}
int ans = 0;
for (int i = 1; i <= 20000; i++)
if (dp[k][i] != -1)
ans = max(ans, min(i, dp[k][i]));
printf("%d
", ans);
}