Uses crt;
Var i,j,N,T,tam : integer;
kt : boolean;
a : array[1..100] Of integer;
Begin
clrscr;
Repeat
write('Nhap N=');
readln(N);
Until (N>=1) And (N<=100);
writeln('Nhap day so nguyen co tri tuyet doi<=1000');
For i:=1 To N Do
Begin
Write('a[',i,']=');
readln(a[i]);
End;
For i:=1 To N-1 Do
For j:=i+1 To N Do
If a[i]>a[j] Then
Begin
tam := a[j];
a[j] := a[i];
a[i] := tam;
End;
kt := true;
T := a[2]-a[1];
For i:=1 To N-1 Do
If a[i+1]-a[i]<>T Then kt := False;
If kt=true Then write('Day A la cap so cong')
Else write('Day A khong la cap so cong');
Readln
End.