#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MOD 1000000007
void solve(){
int n, m;
cin >> n >> m;
vector<int> s(n), f(m);
bool sb2 = (n % 3 == 0);
for(int i = 0 ;i < n; i ++){
cin >> s[i];
}
for(int i = 0 ;i < n; i ++){
if(i % 3 == 1 and i != n - 1 and (s[i] != s[i - 1] or s[i] != s[i + 1])){
sb2 = 0;
}
}
for(int i = 0 ;i < m; i ++){
cin >> f[i];
}
if(n == 1){
if (s[0] <= f[0]) {
cout << (f.back() - s[0]) << endl << "R" << endl;
}
else if (s[0] >= f.back()) {
cout << (s[0] - f[0]) << endl << "L" << endl;
}
else {
cout << -1 << endl;
}
return ;
}
if(sb2){
int r = 0;
for (int i = 0, j = 0; j < m; j++) {
while (i < n - 2 and s[i + 1] < f[j]){
i++;
}
r = max(r, min(abs(f[j] - s[i]), abs(f[j] - s[i + 1])));
}
cout << r << '\n';
for (int i = 0; i < n; i += 3){
cout << "LLR";
}
return ;
}
}
int main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
ll tests = 1;
// cin >> tests;
for(ll i = 1; i <= tests; i++){
solve();
}
}
