import java.io.PrintWriter import java.util.* import kotlin.math.* fun PrintWriter.solve() { val numCases = nextInt() case@ for (_i in 0 until numCases) { val a = nextLong() val b = nextLong() // region divisors val number = b - a val divs = mutableListOf() var divisor = 1L while (divisor * divisor <= number) { if (number % divisor == 0L) { divs.add(divisor) if (divisor * divisor != number) { divs.add(number / divisor) } } divisor++ } // endregion var ans = Long.MAX_VALUE for (d in divs) { val x = (b - a) / d - a if (x >= 0 && (b + x) % (a + x) == 0L) { ans = minOf(ans, x) } } println(if (ans == Long.MAX_VALUE) -1 else ans) } } fun main() { Thread(null, { val writer = PrintWriter(System.out, false) writer.solve() writer.flush() }, "solve", abs(1L.shl(26))) .apply { setUncaughtExceptionHandler { _, e -> e.printStackTrace(); kotlin.system.exitProcess(1) } } .apply { start() }.join() } // region Scanner private var st = StringTokenizer("") private val br = System.`in`.bufferedReader() fun next(): String { while (!st.hasMoreTokens()) st = StringTokenizer(br.readLine()) return st.nextToken() } fun nextInt() = next().toInt() fun nextLong() = next().toLong() fun nextLine() = br.readLine() fun nextDouble() = next().toDouble() // endregion