#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
const int INF = (1 << 30) - 1;
const int MAXN = 100010;
int n, q;
char s[200010];
struct Node {
  int s[5][5];
} DP[200010 << 2];
inline void Init(Node &dp) {
  for (int i = 0; i < 5; ++i)
    for (int j = 0; j < 5; ++j) dp.s[i][j] = 200000;
}
inline void Push_up(Node &dp, Node &dp1, Node &dp2) {
  Init(dp);
  for (int i = 0; i < 5; ++i) {
    for (int j = i; j < 5; ++j) {
      for (int k = i; k <= j; ++k) {
        dp.s[i][j] = min(dp.s[i][j], dp1.s[i][k] + dp2.s[k][j]);
      }
    }
  }
}
void Build(int p, int l, int r) {
  Init(DP[p]);
  if (l == r) {
    for (int i = 0; i < 5; ++i) DP[p].s[i][i] = 0;
    if (s[l] == '2')
      DP[p].s[0][1] = 0, DP[p].s[0][0] = 1;
    else if (s[l] == '0')
      DP[p].s[1][2] = 0, DP[p].s[1][1] = 1;
    else if (s[l] == '1')
      DP[p].s[2][3] = 0, DP[p].s[2][2] = 1;
    else if (s[l] == '6')
      DP[p].s[3][3] = 1, DP[p].s[4][4] = 1;
    else if (s[l] == '7')
      DP[p].s[3][4] = 0, DP[p].s[3][3] = 1;
    return;
  }
  int mid = ((l) + ((r) - (l)) / 2);
  Build(p << 1, l, mid);
  Build(p << 1 | 1, mid + 1, r);
  Push_up(DP[p], DP[p << 1], DP[p << 1 | 1]);
}
Node Query(int a, int b, int p, int l, int r) {
  if (a <= l && r <= b) return DP[p];
  int mid = ((l) + ((r) - (l)) / 2);
  Node res, L, R;
  bool fL = 0, fR = 0;
  if (a <= mid) fL = 1, L = Query(a, b, p << 1, l, mid);
  if (b > mid) fR = 1, R = Query(a, b, p << 1 | 1, mid + 1, r);
  if (fL) {
    if (fR) {
      Push_up(res, L, R);
      return res;
    } else
      return L;
  } else
    return R;
}
int main() {
  scanf("%d%d", &n, &q);
  scanf("%s", s + 1);
  Build(1, 1, n);
  for (int i = 1; i <= q; ++i) {
    int a, b;
    scanf("%d%d", &a, &b);
    Node res = Query(a, b, 1, 1, n);
    printf("%d\n", res.s[0][4] >= 200000 ? -1 : res.s[0][4]);
  }
  return 0;
}
