#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <iostream>
#include <cassert>
#include <cstring>
#include <map>

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)

#define TRACE(x) cerr << #x << " = " << x << endl
#define _ << " _ " <<

#define pb push_back
#define X first
#define Y second

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

const int MAX = 1<<17, TOUR = 1<<17;

int poc[MAX], kraj[MAX];
int st[MAX], ind[MAX];
map <P, int> M_ind;
P spaja[MAX];
int w[MAX];
int root[MAX], sz[MAX]; //-1, 1
P kveri[MAX];

int rje[MAX];
int bre=0;

int find(int x) {
  if (root[x] == -1) return x;
  return find(root[x]);
}

void odspoji(int a, int b) {
  if (sz[a] < sz[b]) swap(a, b);
  sz[a] -= sz[b];
  root[b] = -1;
}

void spoji(int a, int b) { //pazi a = find(a), b = find(b)
  //  a = find(a), b = find(b);
  if (a == b) return;
 
  if (sz[a] < sz[b]) swap(a, b);
  sz[a] += sz[b];
  root[b] = a;
}

vector <int> V[2*TOUR];

void stavi(int pos, int lo, int hi, int begin, int end, int i) {
  if (lo >= end || hi <= begin) return;
  if (lo >= begin && hi <= end) {
    V[pos].push_back(i);
    return;
  }

  stavi(2*pos+0, lo, (lo+hi)/2, begin, end, i);
  stavi(2*pos+1, (lo+hi)/2, hi, begin, end, i);
}

int tez;
void dfs(int pos) {
  vector <P> Bitan;
  
  REP(i, (int) V[pos].size()) {
    auto it = V[pos][i];
    int a = find(spaja[it].X), b = find(spaja[it].Y);
    if (a != b) {
      //      Bitan[i] = 1;
      Bitan.push_back(P(a, b));
      spoji(a, b);
    }
  }

  
  if (pos >= TOUR) {
    int tmp = pos - TOUR;
    if (st[tmp] == 2) {
      if (find(kveri[tmp].X) == find(kveri[tmp].Y))
	rje[tmp] = min(rje[tmp], tez);
    }      
  }
  else {
    dfs(2*pos);
    dfs(2*pos+1);
  }

  reverse(Bitan.begin(), Bitan.end());

  for (auto it : Bitan)
    odspoji(it.X, it.Y);
}

void solve(int tezina) {
  tez = tezina;
  
  REP(i, MAX) {
    root[i] = -1;
    sz[i] = 1;
  }
  REP(i, 2*TOUR) V[i].clear();

  REP(i, bre) {
    //    TRACE(i _ poc[i] _ kraj[i] _ w[i] _ spaja[i].X _ spaja[i].Y);
    if (w[i] > tezina) continue;
    stavi(1, 0, TOUR, poc[i], kraj[i], i);
  }

  dfs(1);  
}


int main(){
  ios_base::sync_with_stdio(false);
  REP(i, MAX) rje[i] = 10000, kraj[i] = -1;  

  int n, q;
  scanf("%d%d", &n, &q);

  REP(i, q) {
    int stanje;
    scanf("%d", &stanje);
    st[i] = stanje;

    if (st[i] == 0) {
      int x, y, v;
      scanf("%d%d%d", &x, &y, &v);
      assert(v >= 0 && v < 10);
      if (x > y) swap(x, y);
      
      M_ind[P(x, y)] = bre;
      ind[i] = bre;
      w[bre] = v;
      poc[bre] = i;
      spaja[bre++] = P(x, y);
    }
    else if (st[i] == 1) {
      int x, y;
      scanf("%d%d", &x, &y);
      if (x > y) swap(x, y);

      int tmp = M_ind[P(x, y)];
      ind[i] = tmp;
      kraj[tmp] = i;
    }
    else {
      int x, y;
      scanf("%d%d", &x, &y);
      if (x > y) swap(x, y);
      kveri[i] = P(x, y);
    }    
  }

  REP(i, MAX) if (kraj[i] == -1) kraj[i] = TOUR-1;
  
  REP(i, 10) solve(i);

  REP(i, q)
    if (st[i] == 2)
      printf("%d\n", rje[i] > 15 ? -1 : rje[i]);
  
  return 0;
}