import sys
n = int(input())
if n < 2:
    print(1)
    sys.exit()
a, b = 1, 1
for i in range(n-1):
    c = a + b
    a = b
    b = c
print(c) import sys sys n = int(input()) n int(input()) int input() input if n < 2:
    print(1)
    sys.exit() n < 2 n 2 print(1) print 1 sys.exit() sys.exit sys exit a, b = 1, 1 a 1 b 1 for i in range(n-1):
    c = a + b
    a = b
    b = c i range(n-1) range n-1 n 1 c = a + b c a + b a b a = b a b b = c b c print(c) print c b = c c b n = int(input()) int(input()) n c = a + b a + b c a = b b a a, b = 1, 1 1 a b = 1, 1 1 b
import sys
n = int(input())
if n < 2:
    print(1)
    sys.exit()
a, b = 1, 1
for i in range(n-1):
    c = a + b
    a = b
    b = c
print(c)
