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

n,Q=map(int,input().split())
s=list(map(int,input()))[::-1]
s+=list(range(1,10))*4

y=[[-1]*len(s) for i in range(10)]
for i in range(len(s)):
  y[s[i]][i]=i
for j in range(10):
  for i in reversed(range(len(s)-1)):
    if y[j][i]==-1:
      y[j][i]=y[j][i+1]

X=10**8

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
  ans=X
  for v in p:
    p1,p2,p3=v
    z=[]
    ll=l
    z+=[y[p1][ll]]
    ll=l
    if p2==p1:
      ll=z[0]+1
    z+=[y[p2][ll]]
    ll=l
    if p3==p1:
      ll=z[0]+1
    if p3==p2:
      ll=z[1]+1
    z+=[y[p3][ll]]
    if max(z)>r:
      continue
    p1,p2,p3=z
    p1-=l
    p2-=l
    p3-=l
    a=(p1-0)+(p2-1)+(p3-2)
    a+=p2<p1
    a+=p3<p1
    a+=p3<p2
    ans=min(ans,a)
  print(ans if ans<X else -1)