#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001

int main(){
	
	int n;
	cin>>n;
	vector<long long> dp(3,0);
	dp[1] = -Inf64,dp[2] = -Inf64;
	rep(i,n){
		long long a;
		cin>>a;
		vector<long long> ndp = dp;
		{
			ndp[1] = max(ndp[1],dp[0] - a);
		}
		{
			ndp[2] = max(ndp[2],dp[1] + a);
		}
		{
			ndp[1] = max(ndp[1], dp[2] - a);
		}
		swap(dp,ndp);
	}
	cout<<max(dp[1],dp[2])<<endl;
    return 0;
}