{$apptype console}

var a,b:array[0..4000] of integer;
i,ax,by,x,y,r,aa,bb:integer;
begin

readln(a[0]);for i:=1 to a[0] do read(a[i]);
//a[i]:=random(9)+1;
{a[0]:=6;
a[1]:=1;
a[2]:=3;
a[3]:=8;
a[4]:=3;
a[5]:=8;
a[6]:=4;}
for i:=1 to a[0] do write(a[i]);
writeln;


if a[0] mod 2=1 then begin
for i:=a[0] downto 1 do a[i+1]:=a[i];
a[0]:=a[0]+1;
a[1]:=0;
end;
b[0]:=0;
i:=1;
b[0]:=b[0]+1;
b[b[0]]:=trunc(sqrt(a[i]*10+a[i+1]));
R:=a[i]*10+a[i+1]-sqr(b[b[0]]);
AA:=R*100+a[i+2]*10+a[i+3];
AX:=2*b[b[0]];
b[0]:=b[0]+1;
for x:=0 to 9 do
if (ax*10+x)*x<=AA then b[b[0]]:=x;
AX:=AX*10+b[b[0]];
i:=5;

// cikl
while i<a[0] do begin

BB:=(AA-AX*b[b[0]])*100+a[i]*10+a[i+1];

BY:=2*(b[b[0]-1]*10+b[b[0]]);
b[0]:=b[0]+1;
for y:=0 to 9 do
if (BY*10+y)*y<=BB then b[b[0]]:=y;
AX:=AX*10+b[b[0]];
AA:=BB;

i:=i+2;
end;

for i:=1 to b[0] do write(b[i]);
writeln;
readln;
readln;
//372
end.