def main():
    def fib(n):
        a = 1
        b = 1
        if n == 0:
            return a
        elif n == 1:
            return b
        else:
            for i in range(n-1):
                a, b = b, a + b
            return b
    
    n = int(input())
    print(fib(n))
        
if __name__ == '__main__':
    main() def main():
    def fib(n):
        a = 1
        b = 1
        if n == 0:
            return a
        elif n == 1:
            return b
        else:
            for i in range(n-1):
                a, b = b, a + b
            return b
    
    n = int(input())
    print(fib(n))
         main def fib(n):
        a = 1
        b = 1
        if n == 0:
            return a
        elif n == 1:
            return b
        else:
            for i in range(n-1):
                a, b = b, a + b
            return b
    
     fib a = 1 a 1 b = 1 b 1 if n == 0:
            return a
        elif n == 1:
            return b
        else:
            for i in range(n-1):
                a, b = b, a + b
            return b
    
     n == 0 n 0 return a a elif n == 1:
            return b
         n == 1 n 1 return b b for i in range(n-1):
                a, b = b, a + b
             i range(n-1) range n-1 n 1 a, b = b, a + b a b b a + b a b return b b n n n = int(input()) n int(input()) int input() input print(fib(n)) print fib(n) fib n if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    def fib(n):
        a = 1
        b = 1
        if n == 0:
            return a
        elif n == 1:
            return b
        else:
            for i in range(n-1):
                a, b = b, a + b
            return b
    
    n = int(input())
    print(fib(n))
         def main():
    def fib(n):
        a = 1
        b = 1
        if n == 0:
            return a
        elif n == 1:
            return b
        else:
            for i in range(n-1):
                a, b = b, a + b
            return b
    
    n = int(input())
    print(fib(n))
         main
def main():
    def fib(n):
        a = 1
        b = 1
        if n == 0:
            return a
        elif n == 1:
            return b
        else:
            for i in range(n-1):
                a, b = b, a + b
            return b
    
    n = int(input())
    print(fib(n))
        
if __name__ == '__main__':
    main()
