#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5, M = 5;
int a[N], n, Q;
struct Node {
  int mat[M][M];
  Node() {}
  Node(int x) {
    memset(mat, 0x3f, sizeof mat);
    for (int i = 0; i <= M - 1; ++i) mat[i][i] = 0;
    if (x == 2)
      mat[0][0] = 1, mat[0][1] = 0;
    else if (x == 0)
      mat[1][1] = 1, mat[1][2] = 0;
    else if (x == 1)
      mat[2][2] = 1, mat[2][3] = 0;
    else if (x == 7)
      mat[3][3] = 1, mat[3][4] = 0;
    else if (x == 6)
      mat[3][3] = 1, mat[4][4] = 1;
  }
  friend Node operator*(Node a, Node b) {
    Node c(-1);
    memset(c.mat, 0x3f, sizeof mat);
    for (int i = 0; i <= M - 1; ++i)
      for (int j = 0; j <= M - 1; ++j)
        for (int k = 0; k <= M - 1; ++k)
          c.mat[i][j] = min(c.mat[i][j], a.mat[i][k] + b.mat[k][j]);
    return c;
  }
} t[N << 2];
inline void build(int k, int l, int r) {
  if (l == r) {
    t[k] = Node(a[l]);
    return;
  }
  int md = l + r >> 1;
  build(k << 1, l, md), build(k << 1 | 1, md + 1, r);
  t[k] = t[k << 1] * t[k << 1 | 1];
}
Node query(int k, int l, int r, int x, int y) {
  if (x <= l && r <= y) return t[k];
  int md = l + r >> 1;
  Node res(-1);
  if (x <= md) res = res * query(k << 1, l, md, x, y);
  if (y > md) res = res * query(k << 1 | 1, md + 1, r, x, y);
  return res;
}
inline int query(int x, int y) {
  int an = query(1, 1, n, x, y).mat[0][4];
  return an > n ? -1 : an;
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0);
  cin >> n >> Q;
  for (int i = 1; i <= n; ++i) {
    char x;
    cin >> x;
    a[i] = x - '0';
  }
  build(1, 1, n);
  for (int i = 1; i <= Q; ++i) {
    int x, y;
    cin >> x >> y;
    cout << query(x, y) << '\n';
  }
  return 0;
}
