1 //fibonacci,find the nth num. 1 1 2 3 5 8...
2 #include <iostream>
3 using namespace std;
4
5 int fib(int n){
6 if(n==1 || n==2){
7 return 1;
8 }
9 int prev=1;
10 int result=1;
11 n-=2;
12 while(n--){
13 result+=prev;
14 prev=result-prev;
15 }
16 return result;
17 }
18 int main(){
19 int n;
20 while(cin>>n){
21 cout<<fib(n)<<endl;
22 }
23
24 return 0;
25 }