#include <bits/stdc++.h>
using namespace std;
int n, q;
const int N = 2e5 + 10;
const int inf = 1e9;
char s[N];
struct Node {
  Node() {
    for (int i = 0; i < 5; i++) {
      for (int j = 0; j < 5; j++) {
        dp[i][j] = (i == j) ? 0 : inf;
      }
    }
  }
  int dp[5][5];
};
Node operator*(const Node& u, const Node& v) {
  Node ans;
  for (int i = 0; i < 5; i++) {
    for (int j = 0; j < 5; j++) {
      ans.dp[i][j] = inf;
      for (int k = 0; k < 5; k++) {
        ans.dp[i][j] = min(u.dp[i][k] + v.dp[k][j], ans.dp[i][j]);
      }
    }
  }
  return ans;
}
Node nodes[N * 4];
void build_tree(int l, int r, int rt) {
  Node& v = nodes[rt];
  if (l == r) {
    char c = s[l - 1];
    if (c == '2') {
      v.dp[0][0] = 1;
      v.dp[0][1] = 0;
    } else if (c == '0') {
      v.dp[1][1] = 1;
      v.dp[1][2] = 0;
    } else if (c == '1') {
      v.dp[2][2] = 1;
      v.dp[2][3] = 0;
    } else if (c == '7') {
      v.dp[3][3] = 1;
      v.dp[3][4] = 0;
    } else if (c == '6') {
      v.dp[3][3] = 1;
      v.dp[4][4] = 1;
    }
    return;
  }
  int m = (l + r) >> 1;
  build_tree(l, m, 2 * rt);
  build_tree(m + 1, r, 2 * rt + 1);
  v = nodes[2 * rt] * nodes[2 * rt + 1];
}
Node query(int L, int R, int l, int r, int rt) {
  Node& v = nodes[rt];
  if (L <= l && R >= r) return v;
  int m = (l + r) >> 1;
  bool left = false, right = false;
  Node ltemp, rtemp;
  if (L <= m) {
    ltemp = query(L, R, l, m, rt * 2);
    left = true;
  }
  if (R > m) {
    rtemp = query(L, R, m + 1, r, rt * 2 + 1);
    right = true;
  }
  if (left && right) return ltemp * rtemp;
  if (left) return ltemp;
  if (right) return rtemp;
}
int main() {
  scanf("%d %d", &n, &q);
  scanf("%s", s);
  build_tree(1, n, 1);
  for (int i = 0; i < q; i++) {
    int l, r;
    scanf("%d %d", &l, &r);
    Node v = query(l, r, 1, n, 1);
    if (v.dp[0][4] == inf)
      cout << -1 << endl;
    else
      cout << v.dp[0][4] << endl;
  }
  return 0;
}
