uses crt;
var
i,j,k,n,sum:integer;
a:array[1..100] of
integer;
flag:boolean;
begin
flag:=false;
writeln('Input N');
read(n);
writeln('Input
elements');
for i:=1 to n do
read(a[i]);
for i:=1 to n do
for j:=1 to n do
for k:=1 to n do
if (i<>j) and
(j<>k) and (i<>k) then
if a[i]+a[j]+a[k]=0
then
begin
writeln('Yes');
flag:=true;
halt;
end;
if flag=false then
writeln('No');
end.