def main():
    n = int(input())
    fib = [1] * (n + 1)
    for i in range(2, n + 1):
        fib[i] = fib[i - 1] + fib[i - 2]
    print(fib[n])


if __name__ == "__main__":
    main()
 def main():
    n = int(input())
    fib = [1] * (n + 1)
    for i in range(2, n + 1):
        fib[i] = fib[i - 1] + fib[i - 2]
    print(fib[n]) main n = int(input()) n int(input()) int input() input fib = [1] * (n + 1) fib [1] * (n + 1) [1] 1 n + 1 n 1 for i in range(2, n + 1):
        fib[i] = fib[i - 1] + fib[i - 2]
     i range(2, n + 1) range 2 n + 1 n 1 fib[i] = fib[i - 1] + fib[i - 2] fib[i] fib i fib[i - 1] + fib[i - 2] fib[i - 1] fib i - 1 i 1 fib[i - 2] fib i - 2 i 2 print(fib[n]) print fib[n] fib n if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main def main():
    n = int(input())
    fib = [1] * (n + 1)
    for i in range(2, n + 1):
        fib[i] = fib[i - 1] + fib[i - 2]
    print(fib[n]) def main():
    n = int(input())
    fib = [1] * (n + 1)
    for i in range(2, n + 1):
        fib[i] = fib[i - 1] + fib[i - 2]
    print(fib[n]) main
def main():
    n = int(input())
    fib = [1] * (n + 1)
    for i in range(2, n + 1):
        fib[i] = fib[i - 1] + fib[i - 2]
    print(fib[n])


if __name__ == "__main__":
    main()

