#include <bits/stdc++.h>
using namespace std;
struct data {
  int a[6][6];
} t[800500];
int n, m;
char s[205000];
data operator+(data a, data b) {
  data c;
  for (int i = 0; i <= 5; i++)
    for (int j = 0; j <= 5; j++) c.a[i][j] = 1e9;
  for (int i = 0; i <= 5; i++)
    for (int j = 0; j <= 5; j++)
      for (int k = 0; k <= 5; k++)
        c.a[i][j] = min(c.a[i][j], a.a[i][k] + b.a[k][j]);
  return c;
}
void build(int i, int l, int r) {
  int mid = (l + r) / 2;
  if (l == r) {
    for (int j = 0; j <= 5; j++)
      for (int k = 0; k <= 5; k++) t[i].a[j][k] = 1e9;
    for (int j = 0; j <= 5; j++) t[i].a[j][j] = 0;
    if (s[l] == '2') t[i].a[0][0] = 1, t[i].a[0][1] = 0;
    if (s[l] == '0') t[i].a[1][1] = 1, t[i].a[1][2] = 0;
    if (s[l] == '1') t[i].a[2][2] = 1, t[i].a[2][3] = 0;
    if (s[l] == '6')
      t[i].a[3][3] = t[i].a[5][5] = 1, t[i].a[3][4] = t[i].a[5][4] = 0;
    if (s[l] == '7') t[i].a[3][3] = 1, t[i].a[3][5] = 0;
    return;
  }
  build(i * 2, l, mid);
  build(i * 2 + 1, mid + 1, r);
  t[i] = t[i * 2] + t[i * 2 + 1];
}
data ask(int i, int l, int r, int L, int R) {
  if (L <= l && r <= R) return t[i];
  int mid = (l + r) / 2;
  if (R <= mid)
    return ask(i * 2, l, mid, L, R);
  else if (L > mid)
    return ask(i * 2 + 1, mid + 1, r, L, R);
  else
    return ask(i * 2, l, mid, L, R) + ask(i * 2 + 1, mid + 1, r, L, R);
}
int main() {
  scanf("%d%d", &n, &m);
  scanf("%s", s + 1);
  build(1, 1, n);
  for (int i = 1; i <= m; i++) {
    int l, r;
    scanf("%d%d", &l, &r);
    int ans = ask(1, 1, n, l, r).a[0][5];
    printf("%d\n", ans == 1e9 ? -1 : ans);
  }
  return 0;
}
