program zamena;
var
 s,s1,s2:string;
 i,ppss:integer;
begin
 writeln('String:');
 readln(s);
 writeln('Substring to replace:');
 readln(s1);
 writeln('Substring for replacement:');
 readln(s2);
 while pos(s1,s)>0 do
  begin
   ppss:=pos(s1,s);
   delete(s,ppss,length(s1));
   insert(s2,s,ppss);
  end;
 writeln('Result:');
 writeln(s);
 readln
end.