#include <iostream>
#include <algorithm>
#include <iterator>
#include <vector>
#include <set>
using namespace std;

bool check_existence_in_vec(int value, const vector<int> &vec)
{
    return binary_search(vec.begin(), vec.end(), value);
}

int main() {
    int n, m;
    cin >> n >> m;

    int insert;
    vector<int> west, east;
    for (int i = 0; i < n; i++) {
        cin >> insert;
        west.push_back(insert);
    }
    for (int i = 0; i < m; i++) {
        cin >> insert;
        east.push_back(insert);
    }

    long duration = 0;

    vector<int> total_time;
    total_time.insert( total_time.end(), west.begin(), west.end() );
    total_time.insert( total_time.end(), east.begin(), east.end() );

    sort( total_time.begin(), total_time.end() );

    // boolean for ferry
    bool stay_at_east = false;

    for (unsigned int i = 0; i < total_time.size(); i++)
    {
        if ( i == 0)
        {
            // ferry is staying at west at the beginning
            // check if the first vehicle is at west or not
            if (check_existence_in_vec( total_time[0], west) )
            {
                // it takes 100 units of time to escort to the east
                duration = total_time[0] + 100;
                stay_at_east = true;
            }
            // the first vehicle is staying at east
            else
            {
                // go to east and escort the vehicle back to west take 200 units
                duration = total_time[0] + 200;
                stay_at_east = false;
            }
        }
        else // the next cases
        {
            if (stay_at_east) // ferry is at east
            {
                if (check_existence_in_vec(total_time[i], east)) // a vehicle is also at east
                {
                    if (total_time[i] > duration)
                    {
                        int delta = total_time[i] - duration;
                        duration += delta + 100;
                    }
                    else duration += 100;
                    stay_at_east = false;
                }
                else // a vehicle is at west
                {
                    // duration += 100; // tales 100 units to get the west
                    if (total_time[i] > duration)
                    {
                        int delta = total_time[i] - duration;
                        duration += delta + 200;
                    }
                    else duration += 200;
                    stay_at_east = true;
                }
            }
            else // ferry is at west
            {  if (check_existence_in_vec(total_time[i], west)) // a vehicle is also at west
                {
                    if (total_time[i] > duration)
                    {
                        int delta = total_time[i] - duration;
                        duration += delta + 100;
                    }
                    else duration += 100;
                    stay_at_east = true;
                }
                else // a vehicle is at east
                {
                    // duration += 100;
                    if (total_time[i] > duration)
                    {
                        int delta = total_time[i] - duration;
                        duration += delta + 200;
                    }
                    else duration += 200;
                    stay_at_east = false;
                }
            }
        }
    }

    cout << duration << endl;

    return 0;
}