function main(input) {
    var h = input[0].split(" ")[0]-0;
    var w = input[0].split(" ")[1]-0;
    var map = [];
    for(var i=1;i<=h;i++){
        map.push(input[i].split(""));
    }
    for(var i=0;i<h;i++){
        for(var j=0;j<w;j++){
            if(map[i][j] == "#"){
                if(map[i] && (map[i][j-1] == '#' || map[i][j+1] == '#')){
                    continue;
                }
                if((map[i-1] && map[i-1][j] == '#' )|| (map[i+1] && map[i+1][j] == '#')){
                    continue;
                }
                console.log("No");
                return;
            }
        }
    }
    console.log("Yes");
}

main(require('fs').readFileSync('/dev/stdin', 'utf8').trim().split("\n"));


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