# 1000-digit Fibonacci number
# Problem 25
# The Fibonacci sequence is defined by the recurrence relation:
# Fn = Fn1 + Fn2, where F1 = 1 and F2 = 1.
# Hence the first 12 terms will be:
# F1 = 1
# F2 = 1
# F3 = 2
# F4 = 3
# F5 = 5
# F6 = 8
# F7 = 13
# F8 = 21
# F9 = 34
# F10 = 55
# F11 = 89
# F12 = 144
# The 12th term, F12, is the first term to contain three digits.
# What is the first term in the Fibonacci sequence to contain 1000 digits?
z=raw_input('Enter the length of fibonacci series?: ')
y=int(z)
a, b = 0, 1
for x in range(1,y+1):
# print b,
a, b = b, a+b
if len(str(b)) == 1000:
print b
break