#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;

vector<pair<int,int> > vec[1000001];
int dist[1000001];
int prv[1000001];

int main() {
    string line;
    int y=0;
    int n=0;
    while (1) {
        getline(cin, line);
        if (line == "") break;
        if (line[line.size()-1] != ' ') line += ' ';
        //cout<<"line:"<<line.size()<<endl;
        string current = "";
        int x = 0;
        for (int i=0; i<line.size(); i++) {
            char c = line[i];
            if (c == ' ') {
                int v = stoi(current);
                int node = 1 + x + y*n;
                //cout<<"x:"<<x<<" y:"<<y<<" node:"<<node<<" v:"<<v<<endl;
                if (x == 0 && y == 0) {
                    pair<int,int> p;
                    p.first = v;
                    p.second = node;
                    vec[0].push_back(p);
                }
                if (y > 0) {
                    int upper = node - n;
                    //cout<<" upper:"<<upper<<endl;;
                    pair<int,int> p;
                    p.first = v;
                    p.second = node;
                    vec[upper].push_back(p);
                }
                if (x > 0) {
                    int left = node - 1;
                    //cout<<" left:"<<left<<endl;
                    pair<int,int> p;
                    p.first = v;
                    p.second = node;
                    vec[left].push_back(p);
                }
                current = "";
                x++;
            } else {
                current += c;
            }
        }
        //cout<<" po loop x:"<<x<<" y:"<<y<<" n:"<<n<<endl;
        n = x;
        y++;
    }
    int m = y;

   priority_queue<pair<int,int>,  std::vector<pair<int,int> >, std::greater<pair<int,int> > > q;
   for (int i=0; i<=n*m; i++) {
       dist[i] = 1000000001;
       pair<int,int> p;
       p.first = 0;
       p.second = i;
       q.push(p);
   }
   dist[0] = 0;
   while(!q.empty()) {
       int u = q.top().second;
       q.pop();
       if (vec[u].size() > 0) {
           int v = vec[u][0].second;
           int vw = vec[u][0].first;
           if (dist[v] > dist[u] + vw) {
                dist[v] = dist[u] + vw;
                pair<int,int> p;
                p.first = dist[v];
                p.second = v;
                q.push(p);
            }
       }
       if (vec[u].size() > 1) {
            int v = vec[u][1].second;
            int vw = vec[u][0].first;
            if (dist[v] > dist[u] + vw) {
                dist[v] = dist[u] + vw;
                pair<int,int> p;
                p.first = dist[v];
                p.second = v;
                q.push(p);
            }
       }
   }
   //cout<<"n:"<<n<<" m:"<<m<<endl;
//    for (int i=0; i<=m*n; i++) {
//        cout<<"i:"<<i<<" dist:"<<dist[i]<<endl;
//    }
   cout<<dist[m*n]<<endl;


}