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

void main()
{
    auto wab = readln.chomp.split(" ").map!(to!int);
    auto w = wab[0];
    auto a = wab[1];
    auto b = wab[2];

    auto d = a < b ? (b-a-w) : (a-b-w);
    writeln(d < 0 ? 0 : d);
}