public class fab {public static void main(string[] args) {system.out.println(f(30));}public static long f(int index){if(index==1||index==2){return 1;}else{long f1=1l;long f2=1l;long f=0;for(int i=0;i<index-2;i++){f=f1+f2;f1=f2;f2=f;}return f;}}} 20210311