#define _CRT_SECURE_NO_WARNINGS
//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
//#define int ll
//#define endl "\n"
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
#define all(c) (c).begin(), (c).end()
#define loop(i,a,b) for(ll i=a; i<ll(b); i++)
#define rep(i,b) loop(i,0,b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
template<class T> ostream & operator<<(ostream & os, vector<T> const &);
template<int n, class...T> typename enable_if<(n>=sizeof...(T))>::type _ot(ostream &, tuple<T...> const &){}
template<int n, class...T> typename enable_if<(n< sizeof...(T))>::type _ot(ostream & os, tuple<T...> const & t){ os << (n==0?"":" ") << get<n>(t); _ot<n+1>(os, t); }
template<class...T> ostream & operator<<(ostream & os, tuple<T...> const & t){ _ot<0>(os, t); return os; }
template<class T, class U> ostream & operator<<(ostream & os, pair<T,U> const & p){ return os << "(" << p.first << ", " << p.second << ") "; }
template<class T> ostream & operator<<(ostream & os, vector<T> const & v){ rep(i,v.size()) os << v[i] << (i+1==(int)v.size()?"":" "); return os; }
template<class T> inline bool chmax(T & x, T const & y){ return x<y ? x=y,true : false; }
template<class T> inline bool chmin(T & x, T const & y){ return x>y ? x=y,true : false; }
#ifdef DEBUG
#define dump(...) (cerr<<#__VA_ARGS__<<" = "<<mt(__VA_ARGS__)<<" ["<<__LINE__<<"]"<<endl)
#else
#define dump(...)
#endif
// ll const mod = 1000000007;
// ll const inf = 1LL<<60;

typedef int Weight;
struct Edge {
    int src, dst;
    Weight weight;
    Edge(int src_, int dst_, Weight weight_) :
        src(src_), dst(dst_), weight(weight_) { }
};
bool operator < (const Edge &e, const Edge &f) {
    return e.weight != f.weight ? e.weight > f.weight : // !!INVERSE!!
        e.src != f.src ? e.src < f.src : e.dst < f.dst;
}
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;
typedef vector<Weight> Array;
typedef vector<Array> Matrix;

vector<Weight> dijkstra(Graph const & g, int s) {
    const Weight inf = numeric_limits<Weight>::min()/4;
    typedef tuple<Weight,int> State;
    priority_queue<State> q;
    vector<Weight> dist(g.size(), inf);
    dist[s] = 0;
    q.emplace(0,s);
    while (q.size()) {
        Weight d;
        int v;
        tie(d,v) = q.top(); q.pop();
        d *= -1;
        /* if(v == t) return d; */
        if (dist[v] < d) continue;
        rep(i,g[v].size()){
            const Edge &e = g[v][i];
            if (dist[e.dst] > dist[v] + e.weight) {
                dist[e.dst] = dist[v] + e.weight;
                q.emplace(-dist[e.dst], e.dst);
            }
        }
    }
    return dist;
}

vector<Weight> dijkstra(const Matrix &g, int s){
    const int n = g.size();
    const Weight inf = numeric_limits<Weight>::max()/4;
    vector<Weight> dist(n, inf);
    vector<int> used(n);
    dist[s] = 0;
    for(int i = 0; i < n; i++){
        int min_v = -1;
        Weight min_d = inf;
        for(int j = 0; j < n; j++){
            if(!used[j] && min_d > dist[j]){
                min_v = j;
                min_d = dist[j];
            }
        }
        used[min_v] = true;
        /* if(min_v == t) return min_d; */
        for(int j = 0; j < n; j++){
            dist[j] = min(dist[j], dist[min_v] + g[min_v][j]);
        }
    }
    return dist;
}

int main(){
    int n;
    cin >> n;
    int inf = 1e9+10;
    Matrix g(n,Array(n,inf));
    rep(i,n){
        int u;
        cin >> u;
        int k;
        cin >> k;
        rep(i,k){
            int v,c;
            cin >> v >> c;
            g[u][v] = c;
        }
    }
    vector<Weight> dist = dijkstra(g,0);
    rep(i,n){
        cout << i << " " << dist[i] << endl;
    }
}

Measured memory_bytes: 1256