#include <bits/stdc++.h>
#pragma GCC optimize(1)
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-fwhole-program")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-fstrict-overflow")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-skip-blocks")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("-funsafe-loop-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#pragma G++ optimize(1)
#pragma G++ optimize(2)
#pragma G++ optimize(3)
#pragma G++ optimize("Ofast")
#pragma G++ optimize("inline")
#pragma G++ optimize("-fgcse")
#pragma G++ optimize("-fgcse-lm")
#pragma G++ optimize("-fipa-sra")
#pragma G++ optimize("-ftree-pre")
#pragma G++ optimize("-ftree-vrp")
#pragma G++ optimize("-fpeephole2")
#pragma G++ optimize("-ffast-math")
#pragma G++ optimize("-fsched-spec")
#pragma G++ optimize("unroll-loops")
#pragma G++ optimize("-falign-jumps")
#pragma G++ optimize("-falign-loops")
#pragma G++ optimize("-falign-labels")
#pragma G++ optimize("-fdevirtualize")
#pragma G++ optimize("-fcaller-saves")
#pragma G++ optimize("-fcrossjumping")
#pragma G++ optimize("-fthread-jumps")
#pragma G++ optimize("-funroll-loops")
#pragma G++ optimize("-fwhole-program")
#pragma G++ optimize("-freorder-blocks")
#pragma G++ optimize("-fschedule-insns")
#pragma G++ optimize("inline-functions")
#pragma G++ optimize("-ftree-tail-merge")
#pragma G++ optimize("-fschedule-insns2")
#pragma G++ optimize("-fstrict-aliasing")
#pragma G++ optimize("-fstrict-overflow")
#pragma G++ optimize("-falign-functions")
#pragma G++ optimize("-fcse-skip-blocks")
#pragma G++ optimize("-fcse-follow-jumps")
#pragma G++ optimize("-fsched-interblock")
#pragma G++ optimize("-fpartial-inlining")
#pragma G++ optimize("no-stack-protector")
#pragma G++ optimize("-freorder-functions")
#pragma G++ optimize("-findirect-inlining")
#pragma G++ optimize("-frerun-cse-after-loop")
#pragma G++ optimize("inline-small-functions")
#pragma G++ optimize("-finline-small-functions")
#pragma G++ optimize("-ftree-switch-conversion")
#pragma G++ optimize("-foptimize-sibling-calls")
#pragma G++ optimize("-fexpensive-optimizations")
#pragma G++ optimize("-funsafe-loop-optimizations")
#pragma G++ optimize("inline-functions-called-once")
#pragma G++ optimize("-fdelete-null-pointer-checks")
using namespace std;
const int M = 2e5 + 10;
const long long mod = 1e9 + 7;
const int bit = 32;
const long long inf = 0x3f3f3f3f;
const double pi = acos(-1.0);
long long dp[M][3][2][2];
long long a[M];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%lld", &a[i]);
  }
  for (int i = 0; i <= n; i++) {
    for (int j = 0; j < 3; j++) {
      for (int k = 0; k < 2; k++) {
        for (int l = 0; l < 2; l++) dp[i][j][k][l] = -inf * inf;
      }
    }
  }
  if (n == 1) {
    printf("%lld\n", a[1]);
    return 0;
  }
  dp[1][1][1][0] = a[1];
  dp[1][2][0][0] = -a[1];
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j <= 2; j++) {
      for (int k = 0; k < 2; k++) {
        for (int l = 0; l < 2; l++) {
          dp[i + 1][(j + 1) % 3][1][l || k == 1] =
              max(dp[i + 1][(j + 1) % 3][1][l || k == 1],
                  dp[i][j][k][l] + a[i + 1]);
          dp[i + 1][(j + 2) % 3][0][l || k == 0] =
              max(dp[i + 1][(j + 2) % 3][0][l || k == 0],
                  dp[i][j][k][l] - a[i + 1]);
        }
      }
    }
  }
  printf("%lld\n", max(dp[n][1][1][1], dp[n][1][0][1]));
  return 0;
}
