#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
int main() {
  cin.tie(0); cout.tie(0);
  ios::sync_with_stdio(false);
  int N;
  cin >> N;
  vector<int> A(N);
  for(int i = 0; i < N; i++) {
    cin >> A[i];
  }
  vector<long long> dp(2);
  dp[1] = -100000000000000000;
  for(int i = 0; i < N; i++) {
    vector<long long> ndp = dp;
    dp[1] = max(dp[1], dp[0] - A[i]);
    dp[0] = max(dp[0], dp[1] + A[i]);
  }
  long long ans = max(dp[0], dp[1]);
  if(ans == 0) {
    ans = *max_element(A.begin(), A.end()) * -1;
  }
  cout << ans<< '\n';
  return 0;
}