#include <bits/stdc++.h>
#define div /
#define ll long long
#define fore(i, l, r) for(int i=int(l); i<int(r); i++)
#define sz(a) int((a).size())
using namespace std;
const int INF = 1e9;
const int MX = 5e5 + 23;
const int MOD = 1000000007;
const int MAX_N = 5e5+23;
const int N = 1e6;
void solve() {
int n,m;
cin >> n >> m;
int s[n],f[m],ans=INF,ok=1;
string ansString;
fore(i,0,n)
cin >> s[i];
fore(i,0,m)
cin >> f[i];
vector<int>v;
for(int i=0; i<n; i+=3) {
if(s[i] != s[i+1] or s[i+1] != s[i+2])
ok=0;
v.push_back(s[i]);
}
if(ok) {
ans=0;
sort(v.begin(), v.end());
fore(i,0,m) {
int tmp=INF;
auto itr = lower_bound(v.begin(), v.end(), f[i]);
tmp = min(tmp, abs(f[i]-(*itr)));
if(itr - v.begin() > 0) {
itr--;
tmp = min(tmp,abs(f[i]-(*itr)));
}
ans = max(ans,tmp);
}
cout << ans << endl;
fore(i,0,n div 3)
cout << "RRL";
cout << endl;
return;
}
fore(p,0,1024) {
string tmp;
fore(j,0,n) {
tmp+='R';
if((1 << j) & p)
tmp[j] = 'L';
}
int k=0;
fore(i,0,m) {
int tmpK=INF;
fore(j,0,n) {
if(tmp[j] == 'L' and f[i] <= s[j])
tmpK=min(tmpK,abs(s[j]-f[i]));
if(tmp[j] == 'R' and f[i] >= s[j])
tmpK=min(tmpK,abs(s[j]-f[i]));
}
k = max(k,tmpK);
}
if(k < ans) {
ans = k;
ansString = tmp;
}
}
if(ans == INF)
cout << -1 << endl;
else
cout << ans << endl << ansString << endl;
}
int main() {
ios::sync_with_stdio(false);
int t=1;
while(t--) solve();
}
