// Vicfred
// https://atcoder.jp/contests/abc129/tasks/abc129_d
// simulation, emulation, brute force
import std.algorithm;
import std.array;
import std.conv;
import std.stdio;
import std.string;

void main() {
    long h, w;
    readf("%s %s\n", &h, &w);

    string[] s = new string[h];
    foreach(i; 0..h) {
        readf("%s\n", &s[i]);
    }

    long maxima = long.min;
    for(int i = 0; i < h; i++) {
        for(int j = 0; j < w; j++) {
            long squares = 1;
            if(s[i][j] == '#') continue;
            for(int k = i - 1; k >= 0; k--) {
                if(s[k][j] == '#') break;
                squares += 1;
            }
            for(int k = i + 1; k < h; k++) {
                if(s[k][j] == '#') break;
                squares += 1;
            }
            for(int k = j - 1; k >= 0; k--) {
                if(s[i][k] == '#') break;
                squares += 1;
            }
            for(int k = j + 1; k < w; k++) {
                if(s[i][k] == '#') break;
                squares += 1;
            }
            maxima = max(maxima, squares);
        }
    }

    maxima.writeln;
}
