import sys
from time import clock
def main():
    start=clock()
    f=open("in3_1.txt","r")
    n=int(f.read())-1
    f.close()
    pim(n)
    end=clock()
    f2=open("out_31_3_1.txt","a")      
    f2.write("\nTime taken by the program is : %f seconds" %(end-start))
    mem=sys.getsizeof(f)+sys.getsizeof(f2)+sys.getsizeof(n)+1092
    f2.write("\nMemory used by the program is : %d bytes." %mem)
    f2.close()   
def pim(n):
    counta=0        #to count the no. of additions.
    f1=open("out_31_sec3_1.txt","w")
    write=f1.write
    if n<2:
        return 
    if n<3:
        write('2')
        return
    x=5
    temp=[2,3]
    append=temp.append          #In python, local variables are easier to access than global ones.
    l=len
    write('2,3')
    n=n+1
    counta+=1
    while l(temp)<n:
        c=0
        for i in temp:
            if (x%i == 0):
                c=1
                break
        if (c==0):
            append(x)
            write(",%d" %x)
        x+=2
        counta+=1
    f1.write("\nThere are %d additions, 1 subtraction and 1 modulus operation in the program." %counta)
"""The following code is executed to find the memory used by the code in this function.
    It was found to be 1092 bytes. This will be added to the memory usage of main().
    mem1=sys.getsizeof(temp)+sys.getsizeof(f1)+sys.getsizeof(append)+sys.getsizeof(write)+sys.getsizeof(x)+sys.getsizeof(l)+sys.getsizeof(i)+sys.getsizeof(c)
    print mem1   
    """
main()