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**10

def solve(l,r,p):
  p1,p2,p3=p
  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:
    return X
  z[0]-=l
  z[1]-=l
  z[2]-=l
  p1,p2,p3=z
  a=(p1-0)+(p2-1)+(p3-2)
  a+=p2<p1
  a+=p3<p1
  a+=p3<p2
  return a

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(solve(l,r,v) for v in p)
  print(a if a<X else -1)