import std.algorithm, std.array, std.container, std.range;
import std.numeric, std.math, std.bigint, std.bitmanip, std.random;
import std.string, std.conv, std.stdio, std.typecons;

void main()
{
  auto rd = readln.split.map!(to!int);
  auto x = rd[0], y = rd[1], r = rd[2];

  auto a = x.abs + y.abs;
  a += (((r.to!real ^^ 2 / 2).sqrt) * 2).to!int + 1;
  writeln(a);
}