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

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

    (abs(x) + abs(y) + sqrt(2.0) * r).ceil.writeln;
}