/*

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\n", ans);

}