a = '01234567890123456789'

print('a')
print(a)
print('=========')

print(a[2])
print('=========')

print(a[-2])
print('=========')

print(a[0:5])
print('=========')

print(a[0:-2])
print('=========')

l = len(a)
print(a[0:l:2])
print('=========')
