def main():
    """ ????????? """
    num = int(input().strip())
    F = []
    for n in range(num+1):
        if n < 2:
            F.append(1)
        else:
            F.append(F[n-1] + F[n-2])
    print (F[num])
if __name__ == '__main__':
    main() def main():
    """ ????????? """
    num = int(input().strip())
    F = []
    for n in range(num+1):
        if n < 2:
            F.append(1)
        else:
            F.append(F[n-1] + F[n-2])
    print (F[num]) main """ ????????? """ num = int(input().strip()) num int(input().strip()) int input().strip() ().strip () input strip F = [] F [] for n in range(num+1):
        if n < 2:
            F.append(1)
        else:
            F.append(F[n-1] + F[n-2])
     n range(num+1) range num+1 num 1 if n < 2:
            F.append(1)
        else:
            F.append(F[n-1] + F[n-2])
     n < 2 n 2 F.append(1) F.append F append 1 F.append(F[n-1] + F[n-2]) F.append F append F[n-1] + F[n-2] F[n-1] F n-1 n 1 F[n-2] F n-2 n 2 print (F[num]) print F[num] F num if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    """ ????????? """
    num = int(input().strip())
    F = []
    for n in range(num+1):
        if n < 2:
            F.append(1)
        else:
            F.append(F[n-1] + F[n-2])
    print (F[num]) def main():
    """ ????????? """
    num = int(input().strip())
    F = []
    for n in range(num+1):
        if n < 2:
            F.append(1)
        else:
            F.append(F[n-1] + F[n-2])
    print (F[num]) main
def main():
    """ ????????? """
    num = int(input().strip())
    F = []
    for n in range(num+1):
        if n < 2:
            F.append(1)
        else:
            F.append(F[n-1] + F[n-2])
    print (F[num])
if __name__ == '__main__':
    main()