import strutils

proc input: string =
  while true:
    let t = stdin.readChar
    if t == '\r': discard
    elif t.isSpaceAscii: break
    else: result.safeAdd t

let x, y, x2, y2 = input().parseInt
var offset = 0

if x == y and x2 == y2 and x > x2:
  offset += 1

echo max(x, y) + offset