# http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_A&lang=ja
import sys
read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines

def main():
    n = int(readline())

    dp = [0] * (n+1)
    dp[0] = 1
    dp[1] = 1

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

    print(dp[n])    


if __name__ == "__main__":
    main() import sys sys read = sys.stdin.read read sys.stdin.read sys.stdin sys stdin read readline = sys.stdin.readline readline sys.stdin.readline sys.stdin sys stdin readline readlines = sys.stdin.readlines readlines sys.stdin.readlines sys.stdin sys stdin readlines def main():
    n = int(readline())

    dp = [0] * (n+1)
    dp[0] = 1
    dp[1] = 1

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

    print(dp[n])     main n = int(readline()) n int(readline()) int readline() readline 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 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 if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main readline = sys.stdin.readline sys.stdin.readline readline readlines = sys.stdin.readlines sys.stdin.readlines readlines read = sys.stdin.read sys.stdin.read read def main():
    n = int(readline())

    dp = [0] * (n+1)
    dp[0] = 1
    dp[1] = 1

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

    print(dp[n])     def main():
    n = int(readline())

    dp = [0] * (n+1)
    dp[0] = 1
    dp[1] = 1

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

    print(dp[n])     main
# http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_A&lang=ja
import sys
read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines

def main():
    n = int(readline())

    dp = [0] * (n+1)
    dp[0] = 1
    dp[1] = 1

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

    print(dp[n])    


if __name__ == "__main__":
    main()
