#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
int n, q;
char s[200005];
struct node {
  int dp[5][5];
  node() {
    for (int i = 0; i < 5; i++)
      for (int j = 0; j < 5; j++) dp[i][j] = 1e8;
  }
  void merge_(node nl, node nr) {
    for (int i = 0; i < 5; i++)
      for (int j = i; j < 5; j++)
        for (int k = i; k <= j; k++)
          dp[i][j] = min(dp[i][j], nl.dp[i][k] + nr.dp[k][j]);
    return;
  }
} seg[800005];
void buildTree(int idx, int l, int r) {
  if (l == r) {
    for (int i = 0; i < 5; i++) seg[idx].dp[i][i] = 0;
    int c = s[l - 1] - '0', id = -1;
    if (c == 6)
      seg[idx].dp[3][3] = seg[idx].dp[4][4] = 1;
    else if (c == 7)
      seg[idx].dp[3][4] = 0;
    else if (c == 2)
      id = 0;
    else if (c == 0)
      id = 1;
    else if (c == 1)
      id = 2;
    if (id != -1) {
      seg[idx].dp[id][id] = 1;
      seg[idx].dp[id][id + 1] = 0;
    }
    return;
  }
  buildTree(2 * idx, l, (l + r >> 1));
  buildTree(2 * idx + 1, (l + r >> 1) + 1, r);
  seg[idx].merge_(seg[2 * idx], seg[2 * idx + 1]);
  return;
}
node query(int idx, int l, int r, int &frm, int &to) {
  node ret;
  if (l > to || r < frm) {
    for (int i = 0; i < 5; i++) ret.dp[i][i] = 0;
    return ret;
  }
  if (l >= frm && r <= to) return seg[idx];
  ret.merge_(query(2 * idx, l, (l + r >> 1), frm, to),
             query(2 * idx + 1, (l + r >> 1) + 1, r, frm, to));
  return ret;
}
void solve() {
  cin >> n >> q >> s;
  buildTree(1, 1, n);
  for (int i = 1; i <= q; i++) {
    int a, b;
    cin >> a >> b;
    int ans = query(1, 1, n, a, b).dp[0][4];
    cout << (ans == 1e8 ? -1 : ans) << endl;
  }
  return;
}
int main() {
  solve();
  return 0;
}
