"""
A = 120
for i in range(1,A+1):
    if(A % i == 0):
        print(i)
"""

from math import lcm
A = [1,2,3,4,5,6,8,10,12,15,20,24,30]
#print(lcm(*A))
#print(sum(A))
print(len(A))
print(*A)