Program cifra;
VAR
cifi,cifo:text;
n,c,i,uc,j:longint;
begin
assign(cifi,'cifra.in');reset(cifi);
assign(cifo,'cifra.out');rewrite(cifo);
readln(cifi,n);
for i:=1 to n do
begin
if(i mod 10=1)then
uc:=uc+1;
if(i mod 10=2)then
begin
for j:=1 to i mod 4 do
c:=i*i*c;
uc:=uc+c mod 10;
end;
c:=0;
if(i mod 10=3)then
begin
for j:=1 to i mod 4 do
c:=i*i*c;
uc:=uc+c mod 10;
end;
c:=0;
end;
writeln(cifo,uc mod 10);
end.