program qiuhe;
var n,delta,i,x,t:integer;
begin
readln(n);
delta:=round(sqrt(8*n+1));
x:=round((delta-1)/2);i:=(x*x+x) div 2;
if i=n then writeln(x)
else
begin
repeat
x:=x+1;
i:=i+x;
until (i>n) and (not odd(i-n));
writeln(x);
end;
end.