import java.util.*;

import java.io.*;

class Main {

public static String StringChallenge(String[] strArr) {

// Abdullah Tas

int point = 0 , comma = 0;

for ( int i = 0; i < strArr[0].length(); i++){

char letter = strArr[0].charAt(i);

if(letter=='.') point++;

if (letter==',') comma++;

if(point>1) return "false";

if(Character.isAlphabetic(letter)) return "false";

}

if (comma!=0){

String [] number = strArr[0].split(",");

// 1,453,44,443.03

for ( int i = 1 ; i<number.length-1 ; i++){

if (number[i].length()!=3) return "false";

}

//443.03

if(point!=0){

String last = number[number.length-1].substring(0,number[number.length-1].indexOf(".")); //(0,3)

if(last.length() != 3 ) return "false";

}

if(number[0].length()>3) return "false";

}else{ // 10.00

if(point != 0){

String last = strArr[0].substring(0,strArr[0].indexOf('.'));

if ( last.length() > 3 ) return "false";

}else{

// 1243

if (strArr[0].length() > 3) return "false";

}

}

return "true";

}

public static void main (String[] args) {

// keep this function call here

Scanner s = new Scanner(System.in);

System.out.print(StringChallenge(s.nextLine()));

}

}