```#include<iostream>
#include<vector>
#include<algorithm>
#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    cin >> n;
    vector<int>cost(n,0);
    for(int i = 0;i<n;i++)
        cin>>cost[i];
    vector<int>dp(n+1,INT_MAX-2);
    if(n==1)cout<<"0";
    if(n==2)
    {
        int Ma = min(cost[0],cost[1]);
        cout<<Ma;
    }
    dp[0] = 0;
    dp[1] = 0;
    for(int i = 2;i<=n;i++)
    {
        dp[i] = min(dp[i-1]+cost[i-1],dp[i-2]+cost[i-2]);
    }
    cout<<dp[n];
    return 0;
    
    
}