uses crt;
var a:array[1..100]of integer;
m,n,i,j,k,x,max,min,kq:integer;
begin
clrscr;
write('Nhap n='); readln(n);
for i:=1 to n do
begin
write('A[',i,']='); readln(a[i]);
end;
write('Nhap m='); readln(m);
kq:=maxint;
for j:=0 to n do
if j+m<=n then
begin
for k:=j+1 to m+j do
begin
max:=a[j+1];
min:=a[j+1];
for x:=j+1 to m+j do
begin
if max<a[x] then max:=a[x];
if min>a[x] then min:=a[x];
end;
if kq>max-min then kq:=max-min;
end;
end;
writeln(kq);
readln;
end.