Using R code, output the longest $5$ sentences in a given text file.

text file $="$

There was a steaming mist in all the hollows, and it had roamed in

its forlornness up the hill, like an evil spirit, seeking rest and finding

none. A clammy and intensely cold mist, it made its slow way through

the air in ripples that visibly followed and overspread one another, as

the waves of an unwholesome sea might do$.$ It was dense enough to

shut out everything from the light of the coach$-$lamps but these its own

workings, and a few yards of road; and the reek of the labouring horses

steamed into it$,$ as if they had made it all.

Two other passengers, besides the one, were plodding up the hill by

the side of the mail. All three were wrapped to the cheekbones and over

the ears, and wore jack$-$boots. Not one of the three could have said,

from anything he saw, what either of the other two was like; and each

was hidden under almost as many wrappers from the eyes of the mind,

as from the eyes of the body, of his two companions. In those days, travellers were very shy of being confidential on a short notice, for anybody

on the road might be a robber or in league with robbers. As to the latter, when every posting$-$house and ale$-$house could produce somebody

in $$the Captain$$s$$ pay, ranging from the landlord to the lowest stable

non$-$descript, it was the likeliest thing upon the cards. So the guard of

the Dover mail thought to himself, that Friday night in November, one

thousand seven hundred and seventy$-$five, lumbering up Shooter$$s Hill,

as he stood on his own particular perch behind the mail, beating his feet,

and keeping an eye and a hand on the arm$-$chest before him, where a

loaded blunderbuss lay at the top of six or eight loaded horse$-$pistols,

deposited on a substratum of cutlass. $"$