#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(x) x.begin(), x.end()
#define MOD1 1LL<<61-1
#define MOD2 (1LL<<61)-1
#define MOD3 (1LL<<61-1)
using namespace std;
using ll=long long;
using ld=long double;
using P=pair<ll,ll>;
//#include <atcoder/all>
//using namespace atcoder;
////using mint=static_modint<998244353>;
//using mint=static_modint<1000000007>;
////using mint=modint;
//#pragma GCC target("avx2")
//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
int inf=2147483647;
ll INF=9223372036854775807;
const ld PI=acos(-1);

void yn(bool f){
	if(f)cout<<"Yes"<<endl;
	else cout<<"No"<<endl;
	return;
}

int main(){
	int n;cin>>n;
	vector<int> a(n);
	rep(i,n)cin>>a[i];

	vector<vector<ll>> dp(n+1,vector<ll>(2,-1001001001001001001));
	dp[0][0]=0;

	rep(i,n){
		dp[i+1][0]=max(dp[i][0],dp[i][1]+a[i]);
		dp[i+1][1]=max(dp[i][1],dp[i][0]-a[i]);
	}

	cout<<max(dp[n][0],dp[n][1])<<endl;
}