#include <bits/stdc++.h>

using namespace std;

#define st first
#define nd second
#define PII pair <int, int>

const int N = 1e5 + 7;
const int T = 1 << 17;

int n, q;
int ans[N];
int rep[N], roz[N];

stack <PII> S;
map <PII, int> M;

PII req[N];
vector <PII> tree[10][T + T + 7];

int Find(int a){
	if(rep[a] == a)
		return a;
	return Find(rep[a]);
}

void Union(int u, int v){
	int fu = Find(u), fv = Find(v);
	if(fu == fv){
		S.push({-1, -1});
		return;
	}
	
	if(roz[fu] > roz[fv])
		swap(fu, fv);
	
	roz[fv] += roz[fu];
	rep[fu] = fv;
	S.push({fu, fv});
}

void rmv(){
	PII t = S.top();
	S.pop();
	
	if(t.st == -1)
		return;
	
	rep[t.st] = t.st;
	roz[t.nd] -= roz[t.st];
}

void add2(int w, int u, int v, int c){
	for(int i = c; i < 10; ++i)
		tree[i][w].push_back({u, v});
}

void add(int u, int v, int c, int s, int t){
	s += T, t += T;
	while(s < t){
		if(s & 1)
			add2(s, u, v, c);
		if(!(t & 1))
			add2(t, u, v, c);
		s = (s + 1) / 2;
		t = (t - 1) / 2;
	}
	
	if(s == t)
		add2(s, u, v, c);
}

void go(int t, int u){
	for(auto v: tree[t][u])
		Union(v.st, v.nd);

	if(u >= T){
		if(u > T && u <= q + T && req[u - T].nd != -1 && Find(req[u - T].st) == Find(req[u - T].nd))
			ans[u - T] = t;
	}
	else{
		go(t, u + u);
		go(t, u + u + 1);
	}
	
	for(auto v: tree[t][u])
		rmv();
}

int main(){
	scanf("%d %d", &n, &q);
	for(int i = 1; i <= n; ++i)
		rep[i] = i, roz[i] = 1;
	
	for(int i = 1; i <= q; ++i){
		ans[i] = -1;

		int t;
		scanf("%d", &t);
		
		if(t == 0){
			int u, v, c;
			scanf("%d %d %d", &u, &v, &c);
			u++; v++;
			if(u > v)
				swap(u, v);
			
			req[i] = {c, -1};
			M[{u, v}] = i;
		}
		
		if(t == 1){
			int u, v;
			scanf("%d %d", &u, &v);
			u++; v++;
			if(u > v)
				swap(u, v);
			
			int from = M[{u, v}];
			add(u, v, req[from].st, from, i);
			
			req[i] = {-1, -1};
			M.erase({u, v});
		}
		
		if(t == 2){
			int u, v;
			scanf("%d %d", &u, &v);		
			u++; v++;	
			req[i] = {u, v};
		}
		
		//puts("oki");
	}
	
	for(auto v: M)
		add(v.st.st, v.st.nd, req[v.nd].st, v.nd, q + 1);
	//puts("ok1");
	for(int i = 9; i >= 0; --i)
		go(i, 1);
	//puts("ok2");
	for(int i = 1; i <= q; ++i)
		if(req[i].nd != -1)
			printf("%d\n", ans[i]);
	return 0;
}