''' Purpose: introduce nested looping.
'''

# get number of rows 
reply = input( 'Enter number of rows: ' )
n = int( reply )

# performed the repeated printing of a number series
for r in range( 0, n ) :
    # print a line of the form r+0 r+1 ... r+n-1
    print( 'row',r,':', end=' ')
    for c in range( 0, n ):
        # What do we want to print? r+c (so we need a variable to store the sum of r+c)
        total = r + c
        # Can we use end= to print it?
        print( total, end=' ' ) # print out each c value one after another
    print()

# for each r value we want to do two things:
    # c loop (line 13)
    # print out a blank print to go to the next line of output for the next row (line 18)
# We complete the c loop for each value of r
    # We calculate r + c since c changes and r remains the same for that r value
    # and we print all the c values on the same line using end=' ' to
    # print each number separated by spaces