var i,n,k,s:longword;
f1,f2:text;
begin
assign(f1,'CAU4.INP');reset(f1);
assign(f2,'CAU4.OUT');rewrite(f2);
readln(f1,n);
k:=1;
s:=1;
for i:=1 to n do
begin
if i mod 6=0 then inc(k);
s:=s+k;
if (i-1) mod 6=0 then s:=s-1;
end;
writeln(f2,s);
close(f1);close(f2);
end.
*code gốc sử dụng đệ quy :v
uses crt;
var d,n:word;
procedure try(i,t:word);
var j:word;
begin
if t<n then
for j:=i to 3 do
begin
t:=t+j;
try(j,t);
t:=t-j;
end
else
if t=n then inc(d);
end;
begin
clrscr;
readln(n);
try(1,0);
writeln(d);
readln;
end.
