#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    int boy_count;
    int girl_count;
    cin >> boy_count >> girl_count;

    int boy_max_ce = 0;
    for (int i = 0; i < boy_count; i++) {
        int ce;
        cin >> ce;
        boy_max_ce = max(boy_max_ce, ce);
    }

    int girl_max_ce = 0;
    for (int i = 0; i < girl_count; i++) {
        int ce;
        cin >> ce;
        girl_max_ce = max(girl_max_ce, ce);
    }

    cout << boy_max_ce + girl_max_ce;
    return 0;
}