>>329
import java.math.*;
import java.io.*;

class Main{
public static void main(String args[]){
System.out.println("101010:"+isBinary("101010"));
System.out.println("123456:"+isBinary("123456"));
}
static boolean isBinary(String str){
try{
new BigInteger(str,2);
return(true);
}
catch(Exception e){
return(false);
}
}
}