import os, sys

print 'Input the number of sides of a regular polygon: '
sides = int(raw_input())
lengths=[]
perimeter=0.0
for x in range(sides):
	print 'Input the length of side ', x+1, ' in inches:'
	side=float(raw_input())
	lengths=lengths+[side]
for x in range(sides):
	perimeter=perimeter+lengths[x]
print 'The perimeter of the polygon is: ', perimeter, ' inches.'