p=[]
for i in range(1000):
  if i%8==0:
    v=list(map(int,(str(i).zfill(3))[::-1]))
    if 0 not in v:
      p+=[tuple(v)]

n,Q=map(int,input().split())
s=list(map(int,input()))[::-1]
y=[[] for i in range(10)]
for i in range(n):
  y[s[i]]+=[i]

X=n*3

for i in range(10):
  for j in range(3):
    y[i]+=[X*(i*3+j+1)]

from bisect import bisect_left

d={}
for p1,p2,p3 in p:
  for l in range(n):
    z=[]
    ll=l
    z+=[y[p1][bisect_left(y[p1],ll)]]
    ll=l
    if p2==p1:
      ll=z[0]+1
    z+=[y[p2][bisect_left(y[p2],ll)]]
    ll=l
    if p3==p1:
      ll=z[0]+1
    if p3==p2:
      ll=z[1]+1
    z+=[y[p3][bisect_left(y[p3],ll)]]
    d[(p1,p2,p3,l)]=z

def solve1(l,r,v):
  z=d[v+(l,)]
  if max(z)>r:
    return X
  z[0]-=l
  z[1]-=l
  z[2]-=l
  return solve2(z)

def solve2(z):
  p1,p2,p3=z
  if p1<p2<p3:
    return (p1-0)+(p2-1)+(p3-2)
  if p1<p3<p2:
    return (p1-0)+(p2-1)+(p3-1)
  if p2<p1<p3:
    return (p1-0)+(p2-0)+(p3-2)
  if p2<p3<p1:
    return (p1-0)+(p2-0)+(p3-1)
  if p3<p1<p2:
    return (p1-0)+(p2-1)+(p3-0)
  if p3<p2<p1:
    return (p1-0)+(p2-0)+(p3-0)

for _ in range(Q):
  l,r=map(int,input().split())
  l=n-l
  r=n-r
  l,r=r,l
  if r-l+1==1:
  	print([-1,0][s[l]==8])
  	continue
  if r-l+1==2:
    p1,p2=s[l:l+2]
    if (p2*10+p1)%8==0:
      print(0)
    elif (p1*10+p2)%8==0:
      print(1)
    else:
      print(-1)
    continue
  a=min(solve1(l,r,v) for v in p)
  print(a if a<X else -1)