import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop, std.bitmanip;

const long MOD = 10^^9 + 7;

void main() {
    auto N = readln.chomp.to!int;
    auto A = N.iota.map!(_ => readln.chomp).array;

    auto tate1 = new bool[](N);
    auto tate2 = new bool[](N);
    auto yoko1 = new bool[](N);
    auto yoko2 = new bool[](N);

    foreach (i; 0..N) {
        tate1[i] = iota(N-1).map!(j => A[j][i] == '.').all;
        tate2[i] = iota(1,N).map!(j => A[j][i] == '.').all;
        yoko1[i] = iota(N-1).map!(j => A[i][j] == '.').all;
        yoko2[i] = iota(1,N).map!(j => A[i][j] == '.').all;
    }

    int ans = 0;
    int tmp;

    // tateのみ
    tmp = 0;
    foreach (i; 0..N) tmp += tate1[i] || tate2[i];
    ans = max(ans, tmp);

    // yokoのみ
    tmp = 0;
    foreach (i; 0..N) tmp += yoko1[i] || yoko2[i];
    ans = max(ans, tmp);

    // tate1 + yoko
    tmp = 0;
    foreach (i; 0..N) tmp += tate1[i];
    tmp += yoko1[N-1] || yoko2[N-1];
    ans = max(ans, tmp);

    // tate2 + yoko
    tmp = 0;
    foreach (i; 0..N) tmp += tate2[i];
    tmp += yoko1[0] || yoko2[0];
    ans = max(ans, tmp);

    // yoko1 + tate
    tmp = 0;
    foreach (i; 0..N) tmp += yoko1[i];
    tmp += tate1[N-1] || tate2[N-1];
    ans = max(ans, tmp);

    // yoko2 + tate
    tmp = 0;
    foreach (i; 0..N) tmp += yoko2[i];
    tmp += tate1[0] || tate2[0];
    ans = max(ans, tmp);

    ans.writeln;
}