史上最离谱的代码出现了

#include<bits/stdc++.h>
#define chang using
#define tiao namespace
#define lanqiu std
#define rap int
#define nishiwodenishiwodeshei cin
#define zaikaojinyidianjiukuaibaozha for
#define niganmahaihaiyo return
#define jinitaimei cout
#define IKUN main
chang tiao lanqiu;
rap IKUN(){
	rap n;
	nishiwodenishiwodeshei>>n;
	rap a[n]; 
	a[1]=1;
	a[2]=2;
	zaikaojinyidianjiukuaibaozha(rap i=3;i<=n;i++){
		a[i]=1;
		zaikaojinyidianjiukuaibaozha(rap j=1;j<=i/2;j++){
			a[i]+=a[j];
        }
	}
	jinitaimei<<a[n];
	niganmahaihaiyo 0;
}
//ikun万岁！ikun万岁！ikun万岁！ikun万岁！ikun万岁！ikun万岁！ikun万岁！ikun万岁！