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

char*mmap();

#define rd_skip() while(*rp++>=48)
#define rd(v) long v=0;{long _c;while(_c=*rp++-48,_c>=0)v=v*10+_c;}
#define wt(v) {long _z=v;do*--wp=_z%10+48;while(_z/=10);}
#define MD 1000000007

int d[200000];

main(){
	char*rp=mmap(0l,1l<<25,1,2,0,0ll);
	rd_skip();
	long m=1,n=0;
	while(*rp){
		rd(a);
		d[n++]=m=m*a%MD;
	}
	long z=d[--n],b=2;
	while(n--){
		z+=d[n]*b%MD;
		b=b*3%MD;
	}
	z%=MD;
	char wbuf[64],*wp=wbuf+sizeof wbuf;
	wt(z);
	write(1,wp,wbuf+sizeof wbuf-wp);
	_exit(0);
}