// Author: Robert Jaworski
#include <bits/stdc++.h>
#pragma GCC diagnostic ignored "-Wsign-compare"
using namespace std;
struct SegTree {
static const vector<int>* translation;
int value{}, update_by{}, update_to{-1};
int left, middle, right;
bool minValue{};
unique_ptr<SegTree> l, r;
SegTree(int from, int to) : left(from), middle((from + to) / 2), right(to) {
if (left != right) {
l = make_unique<SegTree>(left, middle);
r = make_unique<SegTree>(middle+1, right);
}
}
int get(int id) {
relax();
if (left == right && left == id)
return value;
if (id <= middle)
return l->get(id);
return r->get(id);
}
void change(int from, int to, int delta) {
if (from <= translation->at(left) && translation->at(right) <= to) {
update_by += delta;
minValue += delta;
return;
}
relax();
if (l && r) {
if (from <= translation->at(middle)) {
l->change(from, to, delta);
}
if (to >= translation->at(middle+1)) {
r->change(from, to, delta);
}
minValue = min(l->minValue, r->minValue);
}
}
void set(int from, int to, int val) {
if (from <= translation->at(left) && translation->at(right) <= to) {
update_to = val;
update_by = 0;
minValue = value;
return;
}
relax();
if (l && r) {
if (from <= translation->at(middle)) {
l->set(from, to, val);
}
if (to >= translation->at(middle+1)) {
r->set(from, to, val);
}
minValue = min(l->minValue, r->minValue);
}
}
void relax() {
if (left == right) {
if (update_to >= 0) value = update_to;
value += update_by;
minValue = value;
}
else {
if (update_to >= 0) {
l->set(translation->at(0), translation->back(), update_to);
r->set(translation->at(0), translation->back(), update_to);
}
l->change(translation->at(0), translation->back(), update_by);
r->change(translation->at(0), translation->back(), update_by);
minValue = min(l->minValue, r->minValue);
}
update_to = -1;
update_by = 0;
}
};
const vector<int>* SegTree::translation = nullptr;
bool check(int K, const std::vector<int>& s, const std::vector<int>& f, SegTree* tree, const vector<int>& c) {
for (int i = 0; i < s.size(); i++) {
if (c[i]) {
tree->change(s[i], s[i] + K, 1);
}
else {
tree->change(s[i] - K, s[i], 1);
}
}
bool covered = tree->minValue > 0;
tree->set(f[0], f.back(), 0);
return covered;
}
bool bruteforce(int N, int M, int K, const vector<int>& s, const vector<int>& f, std::vector<int>& conf) {
SegTree::translation = &f;
SegTree tree(0, M-1);
conf.resize(N, 0);
for (int i = 0; i != N;) {
if (check(K, s, f, &tree, conf)) return true;
for (i = 0; i < N; i++) {
conf[i] ^= 1;
if (conf[i]) break;
}
}
return false;
}
int main() {
int N, M;
cin >> N >> M;
vector<int> s(N, 0), f(M, 0), conf;
for (auto&& x : s) {
cin >> x;
}
for (auto&& x : f) {
cin >> x;
}
if (N == 1) {
if (s.back() <= f[0]) {
cout << (f.back() - s.back()) << endl << "R" << endl;
}
else if (s[0] >= f.back()) {
cout << (s[0] - f[0]) << endl << "L" << endl;
}
else {
cout << -1 << endl;
}
return 0;
}
int maxK = 1;
int K, l, r;
if (bruteforce(N, M, 0, s, f, conf)) {
K = 0;
goto END;
}
while (!bruteforce(N, M, maxK, s, f, conf)) maxK <<= 1;
l = maxK / 2;
r = maxK;
while (l+1 < r) {
int m = (l+r) / 2;
if (bruteforce(N, M, m, s, f, conf)) {
r = m;
}
else {
l = m;
}
}
K = r;
if (!bruteforce(N, M, K, s, f, conf)) {
cout << "Very bad" << endl;
}
END:
cout << K << endl;
for (auto&& x : conf) {
cout << (x ? 'R' : 'L');
}
cout << endl;
return 0;
}
