#include <iostream>
#include <vector>

int table(int64_t t1, int64_t t2)
{
    int64_t diff = std::abs(t1-t2);
    if(diff <= 15) return 7;
    else if(diff <= 23) return 6;
    else if(diff <= 43) return 4;
    else if(diff <= 102) return 2;
    else return 0;
}

int main()
{
    int n, m;
    std::cin >> n >> m;
    std::vector<int64_t> e(n);
    std::vector<int64_t> a(m);
    for(int i=0; i<n; i++)
        std::cin >> e[i];
    for(int i=0; i<m; i++)
        std::cin >> a[i];
    std::vector<int> dp(n+1);
    for(int i=0; i<m; i++)
    {
        std::vector<int> newdp(n+1);
        for(int j=0; j<=n; j++)
        {
            int score = dp[j];
            if(j > 0)
            {
                score = std::max(score, dp[j-1] + table(e[j-1],a[i]));
                score = std::max(score, newdp[j-1]);
            }
            newdp[j] = score;
        }
        dp = newdp;
    }
    std::cout << dp[n] << std::endl;
}