import io
import sys
from collections import defaultdict, deque, Counter
from itertools import permutations, combinations, accumulate
from heapq import heappush, heappop
from bisect import bisect_right, bisect_left
from math import gcd
import math

_INPUT = """\
6
1 1234
5 500
1 99
"""

def input():
  return sys.stdin.readline()[:-1]

def solve(test):
  C,Y=map(int,input().split())
  K=[1,5,10,50,100,500,1000,2000,5000,10000]
  m=[]
  y=Y
  for i in reversed(range(len(K))):
    m.append(y//K[i])
    y%=K[i]
  if Y//100<C: print('cant exchange')
  elif m[-5]>=C: print('no exchange')
  else: print((m[-5]+(C-m[-5]-1)//5+1)*5)

def random_input():
  from random import randint,shuffle
  N=randint(1,10)
  M=randint(1,N)
  A=list(range(1,M+1))+[randint(1,M) for _ in range(N-M)]
  shuffle(A)
  return (" ".join(map(str, [N,M]))+"\n"+" ".join(map(str, A))+"\n")*3

def simple_solve():
  return []

def main(test):
  if test==0:
    solve(0)
  elif test==1:
    sys.stdin = io.StringIO(_INPUT)
    case_no=int(input())
    for _ in range(case_no):
      solve(0)
  else:
    for i in range(1000):
      sys.stdin = io.StringIO(random_input())
      x=solve(1)
      y=simple_solve()
      if x!=y:
        print(i,x,y)
        print(*[line for line in sys.stdin],sep='')
        break

#0:提出用、1:与えられたテスト用、2:ストレステスト用
main(0)