#include <bits/stdc++.h>
using namespace std;
const int nMAX = 200005;
const int INF = 0x3f3f3f3f;
class matState {
 public:
  int d[6][6];
  matState(int c = 0) {
    for (int i = 0; i < 6; i++)
      for (int j = 0; j < 6; j++) d[i][j] = c;
  }
  inline matState operator+(const matState &o) const {
    matState r(INF);
    for (int i = 0; i < 6; i++) {
      for (int j = 0; j < 6; j++) {
        for (int k = 0; k < 6; k++) {
          r.d[i][j] = min(r.d[i][j], d[i][k] + o.d[k][j]);
        }
      }
    }
    return r;
  }
};
int n, q;
int t[6][10];
char s[nMAX];
matState tree[4 * nMAX];
void treeBuild(int i = 1, int le = 1, int ri = n) {
  if (le == ri) {
    int x = s[le] - '0';
    tree[i] = matState(INF);
    for (int j = 0; j < 6; j++) {
      tree[i].d[j][t[j][x]] = 0;
      tree[i].d[j][j] = min(tree[i].d[j][j], 1);
    }
  } else {
    int m = (le + ri) / 2;
    treeBuild(2 * i, le, m);
    treeBuild(2 * i + 1, m + 1, ri);
    tree[i] = tree[2 * i] + tree[2 * i + 1];
  }
}
matState treeQuery(int leQ, int riQ, int i = 1, int le = 1, int ri = n) {
  if (leQ <= ri && le <= riQ) {
    if (leQ <= le && ri <= riQ) {
      return tree[i];
    } else {
      int m = (le + ri) / 2;
      return treeQuery(leQ, riQ, i * 2, le, m) +
             treeQuery(leQ, riQ, i * 2 + 1, m + 1, ri);
    }
  } else {
    matState r(INF);
    for (int i = 0; i < 6; i++) r.d[i][i] = 0;
    return r;
  }
}
void fillT() {
  for (int i = 0; i < 6; i++)
    for (int j = 0; j < 10; j++) t[i][j] = i;
  t[0][2] = 1;
  t[1][0] = 2;
  t[2][1] = 3;
  t[3][7] = 4;
  t[3][6] = 5;
  t[4][6] = 5;
}
int main() {
  ios_base ::sync_with_stdio(false);
  cin.tie(nullptr);
  cin >> n >> q;
  cin >> (s + 1);
  fillT();
  treeBuild();
  while (q--) {
    int le, ri;
    cin >> le >> ri;
    matState s = treeQuery(le, ri);
    cout << (s.d[0][4] == INF ? -1 : s.d[0][4]) << "\n";
  }
  return 0;
}
