//
//
//  Codeforces: ganariya
//  AtCoder: ganariya2525
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//include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <unordered_map>
#include <climits>
#include <set>
#include <unordered_set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <queue>
#include <random>
#include <complex>
#include <regex>
#include <locale>
#include <random>
#include <type_traits>

using namespace std;

#define SHOW_VECTOR(v) {std::cerr << #v << "\t:";for(const auto& xxx : v){std::cerr << xxx << " ";}std::cerr << "\n";}
#define SHOW_MAP(v){std::cerr << #v << endl; for(const auto& xxx: v){std::cerr << xxx.first << " " << xxx.second << "\n";}}

using LL = long long;

//~~~~~~~~~~~~~~~~~~~~~_(＾～＾ ｣ ∠)_~~~~~~~~~~~~~~~~~~~~~

constexpr int MAX_N = 110;
constexpr LL INF = 1e15;

typedef pair<LL, int> P;

void dijkstra(int s, vector<LL> &dist, vector<vector<LL>> &G, int N) {
    dist[s] = 0;
    priority_queue<P, vector<P>, greater<>> Q;
    Q.push(make_pair(0, s));
    while (!Q.empty()) {
        auto p = Q.top();
        Q.pop();
        LL cost = p.first;
        LL v = p.second;
        if (dist[v] < cost) continue;
        for (int i = 0; i < N; i++) {
            if (G[v][i] == INF)continue;
            if (cost + G[v][i] < dist[i]) {
                dist[i] = cost + G[v][i];
                Q.push(make_pair(dist[i], i));
            }
        }
    }
}

int main() {

    while (true) {

        int n, m;
        cin >> n >> m;

        if (n == 0 && m == 0) break;

        vector<vector<LL>> G(MAX_N, vector<LL>(MAX_N, INF));
        for (int i = 0; i < n; i++) G[i][i] = 0;

        vector<LL> dist;

        for (int i = 0; i < m; i++) {
            int check;
            cin >> check;
            if (check == 0) {
                int s, t;
                cin >> s >> t;
                s--, t--;
                dist = vector<LL>(n, INF);
                dijkstra(s, dist, G, n);
                LL cost = dist[t];
                if(cost == INF) cout << -1 << endl;
                else cout << cost << endl;
            }
            if (check == 1) {
                int u, v;
                LL c;
                cin >> u >> v >> c;
                u--, v--;
                G[u][v] = min(G[u][v], c);
                G[v][u] = min(G[v][u], c);
            }
        }

    }

}







































Measured memory_bytes: 3196