import strutils, sequtils, algorithm, math

var
  xyr = readLine(stdin).split().map(parseFloat)
  maxLen = 0.0

for i in [1.0, -1.0]:
  for j in [1.0, -1.0]:
    maxLen = max(maxLen, abs(xyr[0] + i * xyr[2] * sqrt(2.0) / 2.0) + abs(xyr[1] + j * xyr[2] * sqrt(2.0) / 2.0))

echo(maxLen.ceil().toInt)