# your code goes here
def fib(n):
if n<=0:
return 0
elif n==1:
return 1
else:
return fib(n-1)+fib(n-2)
n=int(input())
if n%2==0:
n=n-2
i=2
count=0
while True:
if count==n:
print(i)
break
i+=1
flag=True
for j in range(2,(i//2)+1):
if i%j==0:
flag=False
break
if flag==True:
count+=1
else:
print(fib(n-2))
IyB5b3VyIGNvZGUgZ29lcyBoZXJlCmRlZiBmaWIobik6CglpZiBuPD0wOgoJCXJldHVybiAwCgllbGlmIG49PTE6CgkJcmV0dXJuIDEKCWVsc2U6CgkJcmV0dXJuIGZpYihuLTEpK2ZpYihuLTIpCgpuPWludChpbnB1dCgpKQppZiBuJTI9PTA6CgluPW4tMgoJaT0yCgljb3VudD0wCgl3aGlsZSBUcnVlOgoJCWlmIGNvdW50PT1uOgoJCQlwcmludChpKQoJCQlicmVhawoJCWkrPTEKCQlmbGFnPVRydWUKCQlmb3IgaiBpbiByYW5nZSgyLChpLy8yKSsxKToKCQkJaWYgaSVqPT0wOgoJCQkJZmxhZz1GYWxzZQoJCQkJYnJlYWsKCQlpZiBmbGFnPT1UcnVlOgoJCQljb3VudCs9MQplbHNlOgoJcHJpbnQoZmliKG4tMikpCgkJCQoJCgoKCQkJCgk=