C Value

/*
    Task    : _example
    Author  : Phumipat C. [MAGCARI]
    Language: C++
    Created : 31 October 2022 [20:37]
*/
#include<bits/stdc++.h>
using namespace std;
long long dp[1000010][3];
int main(){
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);
    int n,num;
    cin >> n;
    for(int i=1;i<=n;i++){
        cin >> num;
        if(i%2 == 1){
            dp[i][0] = dp[i-1][0] - num;
            dp[i][1] = min(dp[i-1][0],dp[i-1][1]) + num;
            dp[i][2] = min(dp[i-1][1],dp[i-1][2]) - num;
        }else{
            dp[i][0] = dp[i-1][0] + num;
            dp[i][1] = min(dp[i-1][0],dp[i-1][1]) - num;
            dp[i][2] = min(dp[i-1][1],dp[i-1][2]) + num;
        }
    }
    cout << min({dp[n][0],dp[n][1],dp[n][2]}) << '\n';
    return 0;
}