import sys
n = int(input())
dp = [0] * (n + 1)
dp[0] = 1
dp[1] = 1
if n == 0:
    print(1)
    sys.exit()
elif n == 1:
    print(1)
    sys.exit()

for i in range(2, n+1):
    dp[i] = dp[i-1] + dp[i-2]

print(dp[n]) import sys sys n = int(input()) n int(input()) int input() input dp = [0] * (n + 1) dp [0] * (n + 1) [0] 0 n + 1 n 1 dp[0] = 1 dp[0] dp 0 1 dp[1] = 1 dp[1] dp 1 1 if n == 0:
    print(1)
    sys.exit()
elif n == 1:
    print(1)
    sys.exit() n == 0 n 0 print(1) print 1 sys.exit() sys.exit sys exit elif n == 1:
    print(1)
    sys.exit() n == 1 n 1 print(1) print 1 sys.exit() sys.exit sys exit for i in range(2, n+1):
    dp[i] = dp[i-1] + dp[i-2] i range(2, n+1) range 2 n+1 n 1 dp[i] = dp[i-1] + dp[i-2] dp[i] dp i dp[i-1] + dp[i-2] dp[i-1] dp i-1 i 1 dp[i-2] dp i-2 i 2 print(dp[n]) print dp[n] dp n n = int(input()) int(input()) n dp = [0] * (n + 1) [0] * (n + 1) dp
import sys
n = int(input())
dp = [0] * (n + 1)
dp[0] = 1
dp[1] = 1
if n == 0:
    print(1)
    sys.exit()
elif n == 1:
    print(1)
    sys.exit()

for i in range(2, n+1):
    dp[i] = dp[i-1] + dp[i-2]

print(dp[n])
