using C=System.Console;class P{static void Main(){for(string s,t="",a="yes",o="([{<)]}>",b="failed at: ";null!=(s=C.ReadLine());a="yes",t=""){for(;s!="";s=s.Substring(1)){int p=o.IndexOf(s[0]);if(p<4)t=o[p+4]+t;else{if(t==""||t[0]!=s[0]){a=b+s;t="";break;}t=t.Substring(1);}}if(t!="")a=b+"EOL";C.WriteLine(a);}}}