static box Main {
  main() {
    local s = "Nyash"
    if s.length() != 5 { print("FAIL: size!=5") return 1 }
    if s.isEmpty() { print("FAIL: isEmpty on non-empty") return 1 }
    if s.substring(0, 2) != "Ny" { print("FAIL: substring") return 1 }
    if s.charAt(2) != "a" { print("FAIL: charAt") return 1 }
    local e = ""
    if not e.isEmpty() { print("FAIL: empty.isEmpty==false") return 1 }
    print("OK: String size/substring/charAt/isEmpty")
    return 0
  }
}

