'use strict'

function main(s) {

  s = s.split('\n')[0].split(' ').map(n => Number(n));

  const w = s[0];
  const a = s[1];
  const b = s[2];

  let ans = 0;

  if ((b + w) < a) ans = a - (b + w);
  if (b > (a + w)) ans = b - (a + w);

  console.log(ans);
}

main(require("fs").readFileSync("/dev/stdin", "utf8"));
