D k 2 a c

D k 2 a cD k 2 a cD k 2 a cD k 2 a cD k 2 a cD k 2 a c
D k 2 a cD k 2 a cD k 2 a cD k 2 a cD k 2 a cD k 2 a c
D k 2 a c