N,Q=map(int,input().split())
S=input()
G=[[] for i in range(10)]
v=[[0]*N for i in range(10)]
for i in range(N):
  x=int(S[i])
  G[x].append(i)
  for y in range(10):
    if y==x:
      v[y][i]=v[y][i-1]+1
    else:
      v[y][i]=v[y][i-1]
for _ in range(Q):
  l,r=map(int,input().split())
  l-=1
  r-=1
  h=[[-10**10]*3 for i in range(10)]
  for x in range(10):
    pos=v[x][r]
    for e in range(pos-1,pos-4,-1):
      if e<0:
        break
      t=G[x][e]
      if t>=l:
        h[x][(pos-1-e)]=t
  result=10**10
  for y in range(13,125):
    z=str(8*y)
    ans=0
    a,b,c=int(z[2]),int(z[1]),int(z[0])
    ans+=r-h[a][0]
    pos1=h[a][0]
    k=0
    if b==a:
      k+=1
    ans+=r-1-h[b][k]
    pos2=h[b][k]
    k=0
    if c==a:
      k+=1
    if c==b:
      k+=1
    ans+=r-2-h[c][k]
    pos3=h[c][k]
    if pos1<pos2:
      ans+=1
    if pos1<pos3:
      ans+=1
    if pos2<pos3:
      ans+=1
    result=min(result,ans)
  if result<10**8:
    print(result)
  else:
    print(-1)