function yoba(n: longword):longword;
var
i: longword;
a: array of longword;
begin
SetLength(a,n+1);
a[1]:=1;
for i:=2 to n do
a[i]:= i - a[a[i-1]];
yoba:=a[n];
end;
begin
writeln(yoba(50000000));
readln;
end.
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