#include <vector>
#include <map>
#include <cassert>
#include <iostream>

using namespace std;
#pragma GCC optimize("O3")

int N,Q;

struct str{
	int ix;
	int type;
	int x,y;
	int end;
	int lvl;
};
const int MAXN = 1e6;
int tab[MAXN];
int Rank[MAXN];

int k;
vector<str> queries;
vector<str> queries_cleared;
int result[MAXN];
map<pair<int, int>, int > M;
vector<str> type2 [MAXN];

void clear_queries()
{
	for(auto const& x : queries)
		if(x.type == 0)
			queries_cleared.push_back(x);
}

int FIND(int k, vector<pair<int, int> > &v)
{
	if(tab[k] == k)
		return k;
	v.push_back({k, tab[k]});
	tab[k] = FIND(tab[k], v);
	return tab[k];
}
void unio(int a, int b, vector<pair<int, int> > & v)
{
	//cerr << a << " "<< b << endl;
	a = FIND(a, v);
	b = FIND(b, v);
	
	if(Rank[a] > Rank[b]) swap(a, b);
	
	v.push_back({ a, tab[a]});
	tab[a] = b;
	Rank[b] += 1;
	v.push_back({-1, b});
	
}

void g(int l, int r, vector<str> const& v)
{
		vector<pair<int, int> > to_rev;
	if(v.size() == 0)
	{
		for(int i=l; i<r; i++)
		{
			for(auto const& x : type2[i])
			{
				if(FIND(x.x, to_rev) == FIND(x.y, to_rev))
					result[x.ix] = k;
			}
		}
		
			for(int i=to_rev.size()-1; i>=0; i--)
	{
		auto const& x = to_rev[i];
		if(x.first == -1)
			Rank[x.second]--;
		else
			tab[x.first] = x.second;
	}
		return;
	}
	//cerr << l<< " " << r << " " << v.size() << endl;
	
	vector<str> vl, vr;
	
	int m = (l+r)/2;
		
	for(auto const& x : v)
	{
		if(x.ix >= r || x.end <= l) continue;
		if(x.ix <= l && x.end >= r)
		{
			unio(x.x, x.y, to_rev);
			continue;
		}
		if(x.ix < m)
			vl.push_back(x);
		if(x.end >= m)
			vr.push_back(x);
	
	}
	
	if(l+1 != r)
	{
		g(l, m, vl);
		g(m, r, vr);
	}
	
	if(l+1 == r)
	{
		for(auto const& x : type2[l])
		{
			if(FIND(x.x, to_rev) == FIND(x.y, to_rev))
				result[x.ix] = k;
		}
	}
	
	
	for(int i=to_rev.size()-1; i>=0; i--)
	{
		auto const& x = to_rev[i];
		if(x.first == -1)
			Rank[x.second]--;
		else
			tab[x.first] = x.second;
	}
}

void f()
{
	for(int i=0; i<=N; i++) { tab[i] = i; Rank[i] = 1; }
	vector<str> v;
	
	for(auto const& x : queries_cleared)
		if(x.type ==  0 && x.lvl <= k)
			v.push_back(x);
	g(0, Q, v);
	
}
int32_t main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> N >> Q;
	for(int i=0; i<Q;i++)
	{
		result[i] = 100;
		str s; 
		cin >> s.type; s.ix = i;
		 
		if(s.type == 2)
		{
			cin >> s.x >> s.y;
			queries.push_back(s);
			type2[i].push_back(s);
			continue;
		}
		
		if(s.type == 0)
		{
			cin >> s.x >> s.y >> s.lvl;
			M[{s.x,s.y}] = i;
			queries.push_back(s);
			continue;
		}
		
		if(s.type == 1)
		{
			cin >> s.x >> s.y;
			queries[M[{s.x,s.y}]].end = i + 1;
			queries.push_back(s);

		}
	}
	
	assert(queries.size() == Q);
	k = 9;
	clear_queries();
	
	while(k >= 0)
	{
		f();
		k--;
	}
	
	for(int i=0; i<Q; i++)
	if(queries[i].type == 2)
	{
		if(result[i] == 100) 
			cout << -1 << endl;
		else
			cout << result[i] << endl;
	}
}