program oken;
uses crt;
var n,i,j,s1,s2,dem: longint;
begin
clrscr;
write('Nhap n: '); readln(n);
for i:=1 to n do
begin
dem:=0;
for j:=2 to (i div 2) do
if (i mod j=0) then
dem:=dem+1;
if dem=0 then
s1:=i;
end;
for i:=(n*10) downto n do
begin
dem:=0;
for j:=2 to (i div 2) do
if (i mod j=0) then
dem:=dem+1;
if dem=0 then
s2:=i;
end;
if s1=s2 then
writeln('So nguyen to gan ',n,' nhat: ',s1)
else if (abs(s1-n))>(s2-n) then
writeln('So nguyen to gan ',n,' nhat: ',s2)
else if (abs(s1-n))<(s2-n) then
writeln('So nguyen to gan ',n,' nhat: ',s1)
else
writeln('So nguyen to gan ',n,' nhat: ',s1,' va ',s2);
readln;
end.