program asd;
uses crt;
const n=20;
var q,x:array[1..n] of integer;
j,l,k,s,i,v:integer;
u:real;
BEGIN clrscr;
randomize;
l:=n;
for i:=1 to l do BEGIN l:=n;
x[i]:=random(60);
write(' ',x[i]);
end ;
writeln;
for j:=1 to 3 do BEGIN v:=1;
for i:=1 to l-1 do BEGIN if x[i]>x[i+1] then q[v]:=x[i]-x[i+1];
if x[i] if x[i]=x[i+1] then q[v]:=x[i];
v:=v+1;
i:=i+1;
end ;
l:=l-trunc(n/2)+1;
for i:=1 to l do BEGIN write(' ',q[i]) ;
x[i]:=q[i] end ;
writeln;
end ;
if x[1]>x[2] then q[1]:=x[1]-x[2];
if x[1] write('l=', q[1]) ;
end .