#include<iostream>
#include<deque>
#include<cstdio>
using namespace std;
int main()
{
    int a[5000][3],n,sz=2;
    scanf("%d",&n);
    for(int i=0;i<n;i++) scanf("%d %d %d",&a[i][0],&a[i][1],&a[i][2]);
    deque<unsigned int> q;
    q.push_back(a[n-1][0]);
    q.push_back(0);
    for(int i=n-2;i>=0;i--)
    {
        unsigned int m=1<<31;
        for(int j=0;j<3;j++)
        {
            if(j<sz&&a[i][j]+q[j]<m) m=a[i][j]+q[j];
        }
        sz++;
        q.push_front(m);
    }
    cout<<q[0]<<endl;
    cin>>n;
}