def fib(n):
    a=[1,1]
    for i in range(2,n+1):
        a.append(a[i-2]+a[i-1])
        i+=1
    return a[-1]
    
n=int(input())
print(fib(n)) def fib(n):
    a=[1,1]
    for i in range(2,n+1):
        a.append(a[i-2]+a[i-1])
        i+=1
    return a[-1]
     fib a=[1,1] a [1,1] 1 1 for i in range(2,n+1):
        a.append(a[i-2]+a[i-1])
        i+=1
     i range(2,n+1) range 2 n+1 n 1 a.append(a[i-2]+a[i-1]) a.append a append a[i-2]+a[i-1] a[i-2] a i-2 i 2 a[i-1] a i-1 i 1 i+=1 i 1 return a[-1] a[-1] a -1 n n n=int(input()) n int(input()) int input() input print(fib(n)) print fib(n) fib n n=int(input()) int(input()) n def fib(n):
    a=[1,1]
    for i in range(2,n+1):
        a.append(a[i-2]+a[i-1])
        i+=1
    return a[-1]
     def fib(n):
    a=[1,1]
    for i in range(2,n+1):
        a.append(a[i-2]+a[i-1])
        i+=1
    return a[-1]
     fib
def fib(n):
    a=[1,1]
    for i in range(2,n+1):
        a.append(a[i-2]+a[i-1])
        i+=1
    return a[-1]
    
n=int(input())
print(fib(n))
