import sys

# sys.setrecursionlimit(200005)
# sys.set_int_max_str_digits(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = -1-(-1 << 31)
inf = -1-(-1 << 62)

# md = 10**9+7
md = 998244353

n, q = LI()
aa = list(map(int, SI()))
idx = [[] for _ in range(8)]

lr = []
for qi in range(q):
    l, r = LI()
    lr.append((qi, l-1, r))

def cal(x, y, z, l, r):
    if not idx[x]:return inf
    if not idx[z]:return inf
    xi=idx[x][-1]
    if xi<l:return inf
    p=-1
    if y==x:p=-2
    if len(idx[y])<-p:return inf
    yi=idx[y][p]
    if yi<l:return inf
    q=-1
    if z==y:
        q=p-1
    elif z==x:
        q=-2
    if len(idx[z])<-q:return inf
    zi=idx[z][q]
    if zi<l:return inf
    res = r-1-xi
    res += r-1-yi-(xi > yi)
    res += r-1-zi-(xi > zi)-(yi > zi)
    return res

ans = [0]*q
lr.sort(key=lambda x: x[-1])
i = 0
for qi, l, r in lr:
    while i < r:
        aa[i] %= 8
        idx[aa[i]].append(i)
        i += 1
    if r-l == 1:
        ans[qi] = 0 if aa[l] == 0 else -1
        continue
    if r-l == 2:
        if (aa[l]*10+aa[l+1])%8 == 0:
            ans[qi] = 0
        elif (aa[l+1]*10+aa[l])%8 == 0:
            ans[qi] = 1
        else:
            ans[qi] = -1
        continue
    cur = inf
    for z in range(8):
        for y in range(8):
            x = (-100*z-10*y)%8
            cur = min(cur, cal(x, y, z, l, r))
    if cur == inf: cur = -1
    ans[qi] = cur

print(*ans,sep="\n")