import java.lang.Math.min

fun main(args: Array<String>) {

    val (d, g) = readLine()!!.split(' ').map(String::toInt)
    val scores = (1..d).map{
        val (p, c) = readLine()!!.split(' ').map(String::toInt)
        listOf(100 * it, p, c)
    }
    var ans = Int.MAX_VALUE
    loop@ for(bit in 0 until (1 shl d)){
        var score = 0
        var num = 0
        for(i in 0 until d){
            if(bit and (1 shl i) != 0){
                score += scores[i][0] * scores[i][1] + scores[i][2]
                num += scores[i][1]
            }
        }

        if(score >= g) {
            ans = min(ans, num)
            continue@loop
        }
        for(i in d-1 downTo 0){
            if(bit and (1 shl i) != 0) continue
            for(j in 0 until scores[i][1]){
                if(score >= g){
                    ans = min(ans, num)
                    continue@loop
                }
                score += scores[i][0]
                num++
            }
        }


    }

//    print(calcF1(g, scores.reversed(), 0))
    print(ans)
}

fun calcF1(goal: Int, probs: List<List<Int>>, acc: Int): Int?{
    val len = probs.size
    fun inI(i : Int, goal: Int, bit: Int, acc: Int): Int?{
        if(goal < 0) return acc
        if(i !in probs.indices) {
            val ps = probs.mapIndexedNotNull{index, list ->  if(1 and (bit shr index) == 1) null else list}
            return calcF2(goal, ps, acc)
        }
        val iscore = probs[i].let { it[0] * it[1] + it[2]}
        return min(inI(i+1, goal - iscore, bit + (1 shl i), acc + probs[i][1]) ?: Int.MAX_VALUE, inI(i+1, goal, bit, acc) ?: Int.MAX_VALUE)
    }
    return inI(0, goal, 0, acc)
}

fun calcF2(goal: Int, probs: List<List<Int>>, acc: Int): Int?{
    if(goal <= 0) return acc
    if(probs.isEmpty()) return null

    val current = probs.first()
    val rest = probs.subList(1, probs.size)

    return (0..current[1]).mapNotNull {i ->
        val score = current[0] * i + if(i == current[1]) current[2] else 0
        calcF2(goal - score, rest, acc + i)
    }.min()
}