그냥 재귀함수로 하면 시간초과 발생! ㅠㅠ
package baekjoon;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class fibonacci_11444 {
public static void main(String args[]) throws IOException {
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
int N=Integer.parseInt(br.readLine());
int sum=0;
int f1=0;
int f2=1;
if(N==1) {sum=1;}
for(int i=0;i<N-1;i++) {
sum=f1+f2;
f1=f2;
f2=sum;
}
System.out.print(sum);
}
}