from math import sqrt,ceil n=10 list=[True]*n list[0]=False list[1]=False root=ceil(sqrt(n)) for i in range(2,root): if list[i]==False: continue for j in range(i+1,len(list)): if j%i==0: list[j]=False sum=0 for i in range(n): if list[i]: sum+=i print(list,sum)