of restriction of freedom to imprisonment, time served on restriction of freedom shall be set off in time imprisonment at the rate one day of imprisonment for one day of restriction of freedom. 53.5. Restriction of freedom is not appointed to the persons recognized as invalids of the first or second group, pregnant women, women having children in the age of till eight years, women and men who have reached a pension age, and also the military men who are taking place at valid urgent military service on an appeal. Article 54. Maintenance in disciplinary military unit 54.1. The maintenance in disciplinary military unit is appointed for the term from three months till two years to the military men, who are taking place at valid urgent military service on an appeal, and also the military men, who are taking place military service under the contract (agreement) on ordinary posts and ensigns, if they did not served provided by law service time at the moment of removal by court of a decision. This punishment shall apply in the cases provided by appropriate articles of the Especial part of the present Code for commitment of crimes against military service, and also in cases when nature of a crime and personality of guilty approve opportunity of replacement of imprisonment for the term not over two years to maintenance of condemned in disciplinary military unit on the same term. 54.2. At replacement of the maintenance in disciplinary military unit to imprisonment term in disciplinary military unit, shall be determined at rate of one day in imprisonment for one day of the maintenance in disciplinary military unit. Article 55. Imprisonment on a certain term 55.1. Imprisonment on a certain term consists in isolation of condemned from a society by his premise in establishments of a settlement type, in establishments on serving punishments of the general, strict or special mode or in prison. The persons, condemned to imprisonment, but did not reach eighteen to the moment of removal by court of a decision, shall be located in educational establishments of general or strengthened regime. 55.2. Imprisonment on the certain term is established for the term from three months up to fifteen years. 55.3. In case of replacement of public works, corrective works or restriction of freedom to imprisonment, it can be appointed for the term of and less than three months. 55.4. In case of partial or full addition of terms of imprisonment at assignment of punishments on sets of crimes, the maximal term of imprisonment there can not be more than fifteen years, or twenty years. Article 56. Definition of establishment kind on serving imprisonment punishments by condemned 56.1. Serving of punishment as imprisonment shall be appointed in the following establishments on serving punishments: 56.1.1. to persons, condemned for crimes, committed on imprudence, to imprisonment for the term of up to five years - in establishments - settlements on serving punishments; 56.1.2. to persons, for the first time condemned to imprisonment for commitment of deliberate crimes, not representing the big public threat or less serious and minor serious crimes, and also to the persons condemned for crimes, accomplished on imprudence, to imprisonment for the term from above five years - in establishments on serving punishments of the general mode; 56.1.3. to the persons, for the first time condemned to imprisonment for commitment of serious crimes, and also at relapse of crimes if condemned served time in imprisonment earlier, and to women at especially dangerous relapse of crimes - in establishments on serving punishments of a strict mode; 56.1.4. at especially dangerous relapse of crimes, and also at replacement of life imprisonment with imprisonment to the certain term - in establishments on serving punishments of a special mode; 15