import std;

void main () {
    int N = readln.chomp.to!int;
    auto c = readln.split.to!(long[]);

    long m = min(c[0], 0);
    long p = max(c[$ - 1], 0);

    long ans = 2 * (abs(m) + abs(p));
    writeln(ans);
}

void read (T...) (string S, ref T args) {
    import std.conv : to;
    import std.array : split;
    auto buf = S.split;
    foreach (i, ref arg; args) {
        arg = buf[i].to!(typeof(arg));
    }
}