#include "bits/stdc++.h"
using namespace std;
#define LL long long
//#define int LL
#define PB push_back
#define VI vector<int>
#define FOR(i,a,b) for(int i = (a); i <= (b); i++)
#define REP(i,n) FOR(i, 0, (int)n - 1)
#define PII pair<int,int>
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define st first
#define nd second

template<class C> void mini(C & a4, C b4){a4 = min(a4, b4);}
template<class C> void maxi(C & a4, C b4){a4 = max(a4, b4);}

template<class TH> void _dbg(const char * sdbg, TH h){
	cerr<<sdbg<<'='<<h<<endl;
}
template<class TH, class... TA> void _dbg(const char * sdbg, TH h, TA... a){
	while(*sdbg!=',')
		cerr<<*sdbg++;
	cerr<<'='<<h<<",";
	_dbg(sdbg + 1, a...);
}
template<class T> ostream & operator<<(ostream & os, vector<T> V){
	os<<"[";for(auto vv: V) os <<vv<<","; return os <<"[";
}
template<class L, class R> ostream & operator<<(ostream & os , pair<L,R> P){
	return os << "(" << P.st <<","<<P.nd<<")";
}
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (__VA_ARGS__)
#define cerr if(0) cout
#endif 
#ifdef LOCAL
const int N = 100005, D = 15, S = 4;
#else
const int N = 100005, D = 15, S = 330;
#endif

int n, q;
int type[N], from[N], to[N], digit[N];

bool vis[N];

int rep[N][D];
int deg[N];
//int size[N][D];
vector<pair<int, int> > V[N][D];

int find(int w, int d) {
	return rep[w][d] = (rep[w][d] == w ? w : find(rep[w][d], d));
}

void Union(int a, int b, int d) {
	//size[find(b, d)][d] += size[find(a, d)][d];
	rep[find(a, d)][d] = find(b, d); 
}

void remove(int a, int d, pair<int, int> p) {
	int x = p.first;
	int y = p.second;
	for (int i = 0; i < V[a][d].size(); i++) {
		if (V[a][d][i] == make_pair(x, y)) {
			swap(V[a][d][i], V[a][d].back());
			V[a][d].pop_back();
			i--;
			continue;
		}
	}	
}

void insert(int x, int y, int d) {
	int a = find(x, d);
	int b = find(y, d);
	V[a][d].push_back({x, y});
	V[b][d].push_back({x, y});
}

vector<int> visited;
bool DFS(int w, int goal, int d) {
	
	if (w == goal) return true;
	vis[w] = true;
	visited.push_back(w);
	for (int i = 0; i < V[w][d].size(); i++) {
		int u = find(V[w][d][i].second, d);
		if (!vis[u] && DFS(u, goal, d)) {
			return true;
		}
	}
	
	return false;
}

bool isPath(int x, int y, int d) {
	int a = find(x, d);
	int b = find(y, d);
	if (a == b) return true;
	bool ret = DFS(a, b, d);
	for (int w : visited) {
		vis[w] = false;
	}
	visited.clear();
	return ret;
}

set<pair<pair<int, int>, int> > currentEdges;
vector<pair<int, int> > interestingEdges;
vector<int> reps;
void preprocess(int fromD) {
//	debug("preprocess", fromD);
	for (int w : reps) {
		for (int d = 0; d < 10; d++) {
			V[w][d].clear();
		}
	}
	reps.clear();
	for (int i = 0; i < n; i++) {
		deg[i] = 0;
		for (int d = 0; d < 10; d++) {
			rep[i][d] = i;
			//size[i][d] = 1;
		}
	}
	interestingEdges.clear();
	for (int i = fromD; i <= min(q, fromD + S - 1); i++) {
		if (type[i] == 1 || type[i] == 0) {
			interestingEdges.push_back({from[i], to[i]});
			deg[from[i]]++;
			deg[to[i]]++;
		}
		if (type[i] == 1) {
				auto x = currentEdges.lower_bound({{from[i], to[i]}, 0});
			if (x->first.first != from[i] || x->first.second != to[i]) {
				continue;
			}
			int d = x->second;
			currentEdges.erase(x);
		//	break;
		} else if (type[i] == 0) {
			currentEdges.insert({{from[i], to[i]}, digit[i]});
		}
	}
	
	sort(interestingEdges.begin(), interestingEdges.end());
	int ptr = 0;
	for (auto e : currentEdges) {
		auto p = e.first;
		while (ptr < interestingEdges.size() && interestingEdges[ptr] < p) {
			ptr++;
		}
		if (ptr < interestingEdges.size() && interestingEdges[ptr] == p) {
			continue;
		}
		for (int d = e.second; d < 10; d++) {
			Union(e.first.first, e.first.second, d);
		}
	}
	
	for (int i = 0; i < n; i++) {
		for (int d = 0; d < 10; d++) {
			if (find(i, d) == i && deg[i] > 0) {
		//		debug(i, d);
				reps.push_back(i);
			}
	    }
	}
}

int32_t main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> n >> q;
	
	for (int i = 1; i <= q; i++) {
		int x, y, v;
		cin >> type[i];
		if (type[i] == 0) {
			cin >> x >> y >> v;
			from[i] = x;
			to[i] = y;
			if (to[i] < from[i]) swap(from[i], to[i]);
			digit[i] = v;
		} else if (type[i] == 1) {
			cin >> x >> y;
			from[i] = x;
			to[i] = y;
			if (to[i] < from[i]) swap(from[i], to[i]);
		} else {
			cin >> x >> y;
			from[i] = x;
			to[i] = y;
			if (to[i] < from[i]) swap(from[i], to[i]);
		}
	}
	
	
	for (int i = 1; i <= q; i++) {
		int x, y, v;
		if (i % S == 1) {
			preprocess(i);
		}
		if (type[i] == 0) {
			x = from[i];
			y = to[i];
			v = digit[i];
			
			for (int d = v; d < 10; d++) {
				insert(x, y, d);
				insert(y, x, d);
			}
		} else if (type[i] == 1) {
			x = from[i];
			y = to[i];
			for (int d = 0; d < 10; d++) {
				int a = find(x, d);
				int b = find(y, d);
				remove(a, d, {x, y});
				remove(b, d, {y, x});
			}	
		} else {
			x = from[i];
			y = to[i];
			bool found = false;
			for (int d = 0; d < 10; d++) {
				if (isPath(x, y, d)) {
					cout << d << endl;
					found = true;
					break;
				}
			}
			if (!found) {
				cout << -1 << endl;
				continue;
			}
		}
	}
	
	return 0;
}