import math



D,G = list(map(int,input().split()))

pc = [list(map(int,input().split()))for _ in range(D)]



digit = "0"+str(D)+"b"

ans = float('INF')

for i in range(2**D):

    flags = list(str(format(i,digit)))

    point = 0

    count = 0

    last0 = -1

    for j in range(D):

        if flags[j] == "1":

            point += pc[j][0]*100*(j+1) + pc[j][1]

            count += pc[j][0]

        else:

            last0 = j

    if point >= G:

        ans = min(ans,count)

    else:

        if last0 != -1:

            r = G - point

            if math.ceil(r/(100*(last0+1))) < pc[last0][0]:

                count += math.ceil(r/(100*(last0+1)))

                ans = min(ans,count)



print(ans)



import math

D,G = list(map(int,input().split()))

PC = [list(map(int,input().split())) for _ in range(D)]



def dfs(d,flag,point,count,tmp):

    point += flag * (PC[d-1][1]+PC[d-1][0]*d*100)

    count += flag * (PC[d-1][0])

    if flag == 0:

        tmp = d

    if d == D:

        if point < G:

            r = math.ceil((G-point)/(tmp*100))

            if r < PC[tmp-1][0]:

                res = count + r

            else:

                res = float("INF")

        else:

            res = count

        return res



    else:

        return min(dfs(d+1,1,point,count,tmp),dfs(d+1,0,point,count,tmp))



print((min(dfs(1,0,0,0,0),dfs(1,1,0,0,0))))
import math

D, G = list(map(int, input().split()))
pc = [list(map(int, input().split())) for _ in range(D)]
digit = "0" + str(D) + "b"
ans = float("INF")
for i in range(2**D):
    flags = list(str(format(i, digit)))
    point = 0
    count = 0
    last0 = -1
    for j in range(D):
        if flags[j] == "1":
            point += pc[j][0] * 100 * (j + 1) + pc[j][1]
            count += pc[j][0]
        else:
            last0 = j
    if point >= G:
        ans = min(ans, count)
    else:
        if last0 != -1:
            r = G - point
            if math.ceil(r / (100 * (last0 + 1))) < pc[last0][0]:
                count += math.ceil(r / (100 * (last0 + 1)))
                ans = min(ans, count)
print(ans)

import math

D, G = list(map(int, input().split()))
PC = [list(map(int, input().split())) for _ in range(D)]


def dfs(d, flag, point, count, tmp):
    point += flag * (PC[d - 1][1] + PC[d - 1][0] * d * 100)
    count += flag * (PC[d - 1][0])
    if flag == 0:
        tmp = d
    if d == D:
        if point < G:
            r = math.ceil((G - point) / (tmp * 100))
            if r < PC[tmp - 1][0]:
                res = count + r
            else:
                res = float("INF")
        else:
            res = count
        return res
    else:
        return min(dfs(d + 1, 1, point, count, tmp), dfs(d + 1, 0, point, count, tmp))


print((min(dfs(1, 0, 0, 0, 0), dfs(1, 1, 0, 0, 0))))

-pc = [list(map(int, input().split())) for _ in range(D)] -digit = "0" + str(D) + "b" -ans = float("INF") -for i in range(2**D): -    flags = list(str(format(i, digit))) -    point = 0 -    count = 0 -    last0 = -1 -    for j in range(D): -        if flags[j] == "1": -            point += pc[j][0] * 100 * (j + 1) + pc[j][1] -            count += pc[j][0] +PC = [list(map(int, input().split())) for _ in range(D)] + + +def dfs(d, flag, point, count, tmp): +    point += flag * (PC[d - 1][1] + PC[d - 1][0] * d * 100) +    count += flag * (PC[d - 1][0]) +    if flag == 0: +        tmp = d +    if d == D: +        if point < G: +            r = math.ceil((G - point) / (tmp * 100)) +            if r < PC[tmp - 1][0]: +                res = count + r +            else: +                res = float("INF") -            last0 = j -    if point >= G: -        ans = min(ans, count) +            res = count +        return res -        if last0 != -1: -            r = G - point -            if math.ceil(r / (100 * (last0 + 1))) < pc[last0][0]: -                count += math.ceil(r / (100 * (last0 + 1))) -                ans = min(ans, count) -print(ans) +        return min(dfs(d + 1, 1, point, count, tmp), dfs(d + 1, 0, point, count, tmp)) + + +print((min(dfs(1, 0, 0, 0, 0), dfs(1, 1, 0, 0, 0))))