#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ent "\n"

const int maxn = 1e6 + 100;
const ll INF = (ll)1e18 + 100;
const int inf = 1e9 + 100;
const int MOD = 1e9 + 7;
const int maxl = 26;
const int P = 31;

int n, m;
vector<pii> g[maxn];
int c[maxn];
bool ok = 1;

void dfs(int v){
	for(auto [to, w]: g[v]){
		if(c[to] < 0){
			c[to] = c[v] ^ 1;
			dfs(to);
		} else if(c[to] == c[v]) ok = 0;
	}
}

void test(){
	cin >> n >> m;
	for(int i = 1; i <= m; i++){
		int a, b, c;
		cin >> a >> b >> c;
		g[a].push_back({b, c});
		g[b].push_back({a, c});
	}
	fill(c, c + n + 1, -1);
	ok = 1; c[1] = 0; dfs(1);
	if(ok){
		cout << 1 << endl;
	} else{
		cout << 2 << endl;
	}
	for(int i = 1; i <= n; i++){
		if(c[i]) cout << 'D';
		else cout << 'R';
	}
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t; t = 1;
    while(t--) test();
    cout << ent;
}