#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

char*mmap();
#define RD(v) int v=0;{int _c;while(_c=*rp++-48,_c>=0)v=v*10+_c;}

#define MD 998244353
#define MD4 (((1+MD)/2+MD)/2)

main(){
	char*rp=mmap(0l,1l<<28,1,2,0,0ll);
	RD(n);
	long z=0;
	n+=2;
	for(int i=2;i<n;++i){
		RD(a);
		z=(z+a*(long)i)%MD;
	}
	n-=2;
	n<<=12;
	long x=1;
	for(int i=0;i<20;++i){
		x=x*x%MD;
		if(n<0) x<<=1;
		n<<=1;
	}
	printf("%d",z*MD4%MD*x%MD);
}