The cost of 10 Perkstars, 12 Kitstars and 15 Munchstars is Rs. 315. The cost of 12 Perkstars, 15 Kitstars and 19 Munchstars is Rs. 389. The cost of 56 Perkstars, 69 Kitstars and “N” Munchstars is Rs. 1797. Find the value of “N” for which the cost of each item cannot be determined uniquely.

1) 68
2) 77
3) 87
4) 81
5) 93