Who will help to arrange comments to the pascal code part 2?

Question

Pascal

The first control, I don’t really understand yet, the programs are also the first. I wrote programs, they seem to work, they are not able to explain)) Help with comments on the following codes:
2.
Const
nn=50;
type
data = record
number : 1..31;
month : 1..12; year :
1901..1997 var d:array[1..nn] of data; i,n,k:integer; s,s1,s2,s3:string; begin Write('Number of dates (1..50)-> '); read(n); Writeln('Enter a space-separated day, month, year: '); for i:=1 to n do Read(d[i].number,d[i].month,d[i].year); { a } Write('Earliest of years: '); k:=d[1].year;
for i:=2 to n do
if d[i].year