#include <iostream>
#include <queue>
#include <map>
#include <string>

using namespace std;

map<string, int> holder;
int d[4] = {1,-1,4,-4};
int in[8];

void dfs(){
            queue<string> que;
                holder["01234567"] = 0;
                    que.push("01234567");
                        while(que.size()){
                                        string cur = que.front();
                                                que.pop();
                                                        int p = cur.find("0");
                                                                for(int i = 0; i < 4; i++){
                                                                                    int np = p + d[i];
                                                                                                if(0<= np && np < 8 && (p !=3 || d[i] != 1) && (p != 4 || d[i] != -1)){
                                                                                                                        string next = cur;
                                                                                                                                        next[p] = cur[np];
                                                                                                                                                        next[np] = '0';
                                                                                                                                                                        if(holder.find(next) == holder.end()){
                                                                                                                                                                                                    holder[next] = holder[cur] + 1;
                                                                                                                                                                                                                        que.push(next);
                                                                                                                                                                                                                                        }
                                                                                                                                                                                    }
                                                                                                        }

                                                                    }
}

void solve(){
            dfs();
                while(cin >> in[0]){
                                for(int i = 1; i < 8; i++){
                                                    cin >> in[i];
                                                            }
                                        string sol = "";
                                                for(int i = 0; i < 8; i++){
                                                                    sol += in[i] + '0';
                                                                            }
                                                        if(holder.find(sol) == holder.end()){
                                                                            cout << -1 << endl;
                                                                                    }else{
                                                                                                        cout << holder[sol] << endl;
                                                                                                                }
                                                            }
}

int main(){
            ios_base::sync_with_stdio(false);
                solve();
                    return 0;
}
