import std.stdio, std.conv, std.string; import std.array, std.range, std.algorithm, std.container; import std.math, std.random, std.bigint, std.datetime, std.format; string read(){ static string[] ss; while(!ss.length) ss = readln.chomp.split; string res = ss[0]; ss.popFront; return res; } int DEBUG_LEVEL = 0; void print()(){ writeln(""); } void print(T, A ...)(T t, lazy A a){ write(t), print(a); } void print(int level, T, A ...)(T t, lazy A a){ if(level <= DEBUG_LEVEL) print(t, a); } void main(string[] args){ if(args.length > 1 && args[1] == "-debug"){ if(args.length > 2 && args[2].isNumeric) DEBUG_LEVEL = args[2].to!int; else DEBUG_LEVEL = 1; } long h = read.to!long; long w = read.to!long; bool[][] xs; foreach(i; 0 .. h){ xs ~= readln.chomp.map!(x => x == '#').array; } string ans = "NO"; bool[][] ys = new bool[][](h, w); foreach(a; 0 .. h) foreach(b; -w .. w){ // h = w = 1 のときでもループが回るように -w からにしている bool flag = 1; if(a == 0 && b == 0) continue; foreach(i; 0 .. h) foreach(j; 0 .. w) ys[i][j] = xs[i][j]; foreach(i; 0 .. h) foreach(j; 0 .. w){ if(! ys[i][j]) continue; if(i + a < h && j + b >= 0 && j + b < w && ys[i + a][j + b]) ys[i + a][j + b] = 0; else flag = 0; } if(flag) ans = "YES"; } ans.writeln; }