#include <iostream>
using namespace std;
struct node{
    int val;
    node* next;
};
void mlist(struct node** tab,int n){ //wypisz
    for(int i = 0; i < n; i++){
        cout << "A[" << i << "] =";
        struct node* p = tab[i];
        while(p)
        {
          cout << "  " << p->val;
          p = p->next;
        }
        cout << endl;
    }
}
int dfs(node** tab,int start,bool visited[]){
    visited[start] = true;
    int ile = 0;
    cout<<start;
    struct node* p = tab[start];
    int pom = 0;
    if(p == NULL){
        ile=ile+1;
    }
    while(p){
        if(visited[p->val] == false) {
            //cout<<endl<<"p->val"<<p->val<<"pom:"<<pom<<endl;
            ile +=  dfs(tab,p->val,visited);
        }
        //ile = ile+pom;
        p=p->next;
    }
    return ile+1;
}

bool canGoAnywhere(int n,int m,int trains[][2]){
    if(m<n-1) {
        cout<<"cannot";
        return false;
    }
    struct node** A = new node * [n];
    bool visited[n] = {false};
    for(int i = 0; i<n; i++) A[i] = NULL;
    for(int i = 0;i<m;i++){
        if(A[trains[i][0]] == NULL){
            struct node* p = new node;
            p->val=trains[i][1];
            p->next=NULL;
            A[trains[i][0]]=p;
        }
        else{
            struct node* q = A[trains[i][0]];
            while(q->next){
                q=q->next;
            }
            struct node* p = new node;
            p->val=trains[i][1];
            p->next=NULL;
            q->next=p;
        }
        if(A[trains[i][1]]==NULL){
            struct node* p = new node;
            p->val=trains[i][0];
            p->next=NULL;
            A[trains[i][1]]=p;
        }
        else{
            struct node* q = A[trains[i][1]];
            while(q->next){
                q=q->next;
            }
            struct node* p = new node;
            p->val=trains[i][0];
            p->next=NULL;
            q->next=p;
        }
    }
    struct node* p = A[0];
    mlist(A,n);
    int res=dfs(A,0,visited);
    if(res==n){
        return true;
    }
    //cout<<endl<<"res: "<<dfs(A,0,visited)<<endl;
    else{
        return false;
    }
    //mlist(A,n);
}

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char** argv) {
    int trains[][2]={{0,1},{1,2},{2,0},{3,4}};
    int n = 5;
    int m = 4;
    //cout<<trains[1][0];
    cout<<canGoAnywhere(n,m,trains);
    return 0;
}