S k 1 n 1 k

S k 1 n 1 kS k 1 n 1 kS k 1 n 1 kS k 1 n 1 kS k 1 n 1 kS k 1 n 1 k
S k 1 n 1 kS k 1 n 1 kS k 1 n 1 kS k 1 n 1 kS k 1 n 1 kS k 1 n 1 k
S k 1 n 1 kS k 1 n 1 k