import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string;

auto rdsp(){return readln.splitter;}
void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;}
void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}

void main()
{
  int n; readV(n);

  if (n == 0) {
    writeln(0);
    return;
  }

  write("0.");
  foreach (i; 0..n) write("142857"[i%6]);
  writeln;
}