#include <bits/stdc++.h>
using namespace std;
long long n, m;
struct matrix {
  long long a[5][5];
  long long n, m;
  matrix() {
    n = m = 0;
    memset(a, 0x3f, sizeof(a));
  }
  inline long long *operator[](long long x) { return a[x]; }
  matrix operator*(matrix b) {
    matrix c;
    c.n = n;
    c.m = b.m;
    for (long long i = 0; i < c.n; ++i)
      for (long long j = 0; j < c.m; ++j)
        for (long long k = 0; k < m; ++k)
          c.a[i][j] = min(c.a[i][j], a[i][k] + b.a[k][j]);
    return c;
  }
};
struct segment_tree {
  long long l, r;
  matrix k;
} tr[200010 << 2];
long long read() {
  long long s = 0, w = 1;
  char c = getchar();
  while ((c < '0' || c > '9') && c != '-') c = getchar();
  if (c == '-') w = -1, c = getchar();
  while (c <= '9' && c >= '0') s = (s << 3) + (s << 1) + c - '0', c = getchar();
  return s * w;
}
char s[200010] = {};
inline void push(long long p) { tr[p].k = tr[p << 1].k * tr[p << 1 | 1].k; }
void build(long long p, long long l, long long r) {
  tr[p].l = l;
  tr[p].r = r;
  if (l == r) {
    tr[p].k.n = tr[p].k.m = 5;
    for (long long i = 0; i < 5; ++i) tr[p].k[i][i] = 0;
    if (s[l] == '2') tr[p].k[0][0] = 1, tr[p].k[0][1] = 0;
    if (s[l] == '0') tr[p].k[1][1] = 1, tr[p].k[1][2] = 0;
    if (s[l] == '1') tr[p].k[2][2] = 1, tr[p].k[2][3] = 0;
    if (s[l] == '7') tr[p].k[3][3] = 1, tr[p].k[3][4] = 0;
    if (s[l] == '6') tr[p].k[3][3] = 1, tr[p].k[4][4] = 1;
    return;
  }
  long long mid = (l + r) >> 1;
  build(p << 1, l, mid);
  build(p << 1 | 1, mid + 1, r);
  push(p);
}
matrix ask(long long p, long long l, long long r) {
  if (l <= tr[p].l && tr[p].r <= r) return tr[p].k;
  long long mid = (tr[p].l + tr[p].r) >> 1;
  if (r <= mid) return ask(p << 1, l, r);
  if (l > mid) return ask(p << 1 | 1, l, r);
  return ask(p << 1, l, r) * ask(p << 1 | 1, l, r);
}
signed main() {
  n = read();
  m = read();
  cin >> (s + 1);
  build(1, 1, n);
  for (long long i = 1; i <= m; ++i) {
    long long x = read(), y = read();
    matrix ans = ask(1, x, y);
    printf("%lld\n", ans[0][4] > n ? -1 : ans[0][4]);
  }
  return 0;
}
