import java.io.IOException

fun main(args: Array<String>) {
    val fs = FastScanner()
    val N = fs.nextInt()

    var t = 1L
    var a = 1L
    for (i in 0 until N) {
        val nt = fs.nextLong()
        val na = fs.nextLong()
        val numT = ceilDiv(t, nt)
        val numA = ceilDiv(a, na)

        val nextT = nt * Math.max(numT, numA)
        val nextA = na * Math.max(numT, numA)
        t = nextT
        a = nextA
    }

    println(t + a)
}

fun ceilDiv(x: Long, y: Long) : Long {
    return 1L + ((x - 1L) / y)
}

fun lowerBound(t: Long, a: Long, nt: Long, na: Long) : Long {
    var ng = -1L
    var ok = Long.MAX_VALUE / 100L

    while (Math.abs(ok - ng) > 1) {
        val mid = (ok - ng) / 2L + ng
        if ((t.toDouble() / mid.toDouble() <= nt && a.toDouble() / mid.toDouble() <= na) ) {
            ok = mid
        } else {
            ng = mid
        }
    }
    return ok
}


internal class FastScanner {
    private val `in` = System.`in`
    private val buffer = ByteArray(1024)
    private var ptr = 0
    private var buflen = 0
    private fun hasNextByte(): Boolean {
        if (ptr < buflen) {
            return true
        } else {
            ptr = 0
            try {
                buflen = `in`.read(buffer)
            } catch (e: IOException) {
                e.printStackTrace()
            }

            if (buflen <= 0) {
                return false
            }
        }
        return true
    }

    private fun readByte(): Int {
        return if (hasNextByte()) buffer[ptr++].toInt() else -1
    }

    private fun isPrintableChar(c: Int): Boolean {
        return 33 <= c && c <= 126
    }

    private fun skipUnprintable() {
        while (hasNextByte() && !isPrintableChar(buffer[ptr].toInt())) ptr++
    }

    operator fun hasNext(): Boolean {
        skipUnprintable()
        return hasNextByte()
    }

    operator fun next(): String {
        if (!hasNext()) return ""
        val sb = StringBuilder()
        var b = readByte()
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b)
            b = readByte()
        }
        return sb.toString()
    }

    fun nextLong(): Long {
        if (!hasNext()) return -1
        var n: Long = 0
        var minus = false
        var b = readByte()
        if (b == '-'.toInt()) {
            minus = true
            b = readByte()
        }
        if (b < '0'.toInt() || '9'.toInt() < b) {
            throw NumberFormatException()
        }
        while (true) {
            if ('0'.toInt() <= b && b <= '9'.toInt()) {
                n *= 10
                n += (b - '0'.toInt()).toLong()
            } else return if (b == -1 || !isPrintableChar(b)) {
                if (minus) -n else n
            } else {
                throw NumberFormatException()
            }
            b = readByte()
        }
    }

    fun nextInt(): Int {
        val set = hashSetOf<Char>()
        set.add('3')
        set.clear()

        if (!hasNext()) return -1
        var n: Int = 0
        var minus = false
        var b = readByte()
        if (b == '-'.toInt()) {
            minus = true
            b = readByte()
        }
        if (b < '0'.toInt() || '9'.toInt() < b) {
            throw NumberFormatException()
        }
        while (true) {
            if ('0'.toInt() <= b && b <= '9'.toInt()) {
                n *= 10
                n += (b - '0'.toInt()).toInt()
            } else return if (b == -1 || !isPrintableChar(b)) {
                if (minus) -n else n
            } else {
                throw NumberFormatException()
            }
            b = readByte()
        }
    }
}

Measured memory_bytes: 31820