// Problem G  Ver. 1.0
// Coding & Debug : 150min

#include <stdio.h>
#include <math.h>
#define PI 3.1415926535897932385

int lines;
struct {
	int len, count;
	int movs;
	int mov[64][3];
} line[6];

int max;
int x,y;
int startdeg;

void find(int l,int deg,int s,int mov[])
{
	int dx = mov[0], dy = mov[1];
	int i,j;
	int d=0;
	if (l<lines-1) {
		d = (mov[2]-startdeg + 1024)&1023;
		if (d<deg && d==0) d=1024;
		if (d<deg || d>1024) return;
	}
	if (l==lines-1) {
		startdeg = mov[2];
	}
	if (l*300<sqrt( (x+dx)*(x+dx) + (y+dy)*(y+dy))) return;
	x+=dx; y+=dy;
	if (l==0) {
		if (x==0 && y==0) {
			if (s>max*2) max = s/2;
		}
		x-=dx; y-=dy;
		return;
	}

	if ( l<lines-1)
		s+=abs((x*(y-dy) - y*(x-dx))); // add to s

	for (i=0;i<6;i++) {
		if (line[i].count<1) continue;
		line[i].count--;
		for (j=0;j<line[i].movs;j++) {
			if (l==lines && j>line[i].movs/4) break;
			if ( (d-line[i].mov[j][2]&1023) > 512) continue;
			find(l-1,d,s,  line[i].mov[j]);
		}
		line[i].count++;
		if (l==lines) break;
	}
	x-=dx; y-=dy;
}

int main()
{
	FILE *fp = fopen("G.txt","r");
	int n,i,j,k,l;
	int dummy[]={0,0,0};

	while(fscanf(fp,"%d",&n) && n) {
		for (j=0;j<6;j++)
			line[j].count = 0;

		k=0;
		for (i=0;i<n;i++) {
			fscanf(fp,"%d",&l);
			for (j=0;j<k;j++) {
				if (line[j].len==l) break;
			}
			line[j].count++;
			if (j==k) {
				int x,y;
				line[j].len = l;
				line[j].count=1;
				line[k].movs = 0;
				for (x=l;x>=-l;x--) {
					for (y=0;y<=l;y++) {
						if (x*x+y*y == l*l) {
							line[k].mov[line[k].movs][0]=x;
							line[k].mov[line[k].movs][1]=y;
							line[k].mov[line[k].movs][2]=(int)((atan2(y,x)+PI)*1024/(2*PI))&1023;
							line[k].movs++;
						}
					}
				}
				for (x=0;x<line[k].movs;x++) {
					line[k].mov[line[k].movs+x][0]=-line[k].mov[x][0];
					line[k].mov[line[k].movs+x][1]=-line[k].mov[x][1];
					line[k].mov[line[k].movs+x][2]=(line[k].mov[x][2]+512)&1023;
				}
				line[k].movs*=2;
				k++;
			}
		}

		max = 0;
		lines = n;
		x = y = 0;
		find(lines,0,0,dummy);
		printf("%d\n",max?max:-1);
	}

	return 0;
}