#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>
#include <limits>
#include <array>

static const int MOD = 998244353;
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;

ll dp[2][200001];

int main() {
    int n;
    cin >> n;
    vector<int> A(n);
    for (auto &&i : A) scanf("%d", &i);
    dp[0][0] = -INF<ll>; dp[1][0] = -INF<ll>;
    for (int i = 0; i < n; ++i) {
        dp[0][i+1] = max(dp[0][i], dp[1][i]+A[i]);
        dp[1][i+1] = max(dp[1][i], max(0LL, dp[0][i])-A[i]);
    }
    cout << max(dp[0][n], dp[1][n]) << "\n";
    return 0;
}