x=int(input())
a=1
b=1
i=1
if x==0:
    print(1)
elif x==1:
    print(1)

else:
    while i<=x-1:
        c=a+b
        a=b
        b=c
        i+=1
    print(c) x=int(input()) x int(input()) int input() input a=1 a 1 b=1 b 1 i=1 i 1 if x==0:
    print(1)
elif x==1:
    print(1)

else:
    while i<=x-1:
        c=a+b
        a=b
        b=c
        i+=1
    print(c) x==0 x 0 print(1) print 1 elif x==1:
    print(1) x==1 x 1 print(1) print 1 while i<=x-1:
        c=a+b
        a=b
        b=c
        i+=1
     i<=x-1 i x-1 x 1 c=a+b c a+b a b a=b a b b=c b c i+=1 i 1 print(c) print c x=int(input()) int(input()) x b=1 1 b a=b b a c=a+b a+b c i+=1 1 i a=1 1 a i=1 1 i b=c c b
x=int(input())
a=1
b=1
i=1
if x==0:
    print(1)
elif x==1:
    print(1)

else:
    while i<=x-1:
        c=a+b
        a=b
        b=c
        i+=1
    print(c)
