Program Copie_ch;
Var
ch1, chr : String;
i, p, n, l : Integer;
Begin
Write ('ch1 = ');
Readln (ch1);
l:=Length (ch1);
Repeat
Write ('Position = ');
Readln (p);
Write ('Nbre caractères = ');
Readln (n);
Until (p in [1..l]) and (n in [1..l]) and (p+n<=l+1);
chr:='';
For i:=p To p+n-1 Do chr:=chr+ch1 [i];
Writeln ('La chaîne copiée est : ', chr);
End.