#include <bits/stdc++.h>
using namespace std;
const int N = 1 << 18;
struct Tuple {
  int dp[5][5];
  Tuple(char c) : Tuple() {
    if (c == '2') {
      dp[0][0] = 1;
      dp[0][1] = 0;
    } else if (c == '0') {
      dp[1][1] = 1;
      dp[1][2] = 0;
    } else if (c == '1') {
      dp[2][2] = 1;
      dp[2][3] = 0;
    } else if (c == '6') {
      dp[3][3] = 1;
      dp[4][4] = 1;
    } else if (c == '7') {
      dp[3][3] = 1;
      dp[3][4] = 0;
    }
  }
  Tuple() {
    for (int i = 0; i < 5; i++) {
      for (int j = 0; j < 5; j++) {
        dp[i][j] = 1e7;
      }
      dp[i][i] = 0;
    }
  }
};
Tuple dat[N * 2];
Tuple operator*(Tuple a, Tuple b) {
  Tuple ret;
  for (int i = 0; i < 5; i++) {
    ret.dp[i][i] = 1e7;
  }
  for (int i = 0; i < 5; i++) {
    for (int j = i; j < 5; j++) {
      for (int k = j; k < 5; k++) {
        ret.dp[i][k] = min(ret.dp[i][k], a.dp[i][j] + b.dp[j][k]);
      }
    }
  }
  return ret;
}
Tuple query(int l, int r) {
  Tuple vl, vr;
  l += N;
  r += N;
  for (; l < r; l /= 2, r /= 2) {
    if (l & 1) vl = vl * dat[l++];
    if (r & 1) vr = dat[--r] * vr;
  }
  return vl * vr;
}
int main() {
  int n, q;
  cin >> n >> q;
  string s;
  cin >> s;
  for (int i = 0; i < n; i++) {
    dat[i + N] = Tuple(s[i]);
  }
  for (int i = N - 1; i >= 1; i--) {
    dat[i] = dat[i * 2] * dat[i * 2 + 1];
  }
  for (int i = 0; i < q; i++) {
    int l, r;
    scanf("%d %d", &l, &r);
    Tuple ret = query(l - 1, r);
    int ans = ret.dp[0][4];
    if (ans > n) ans = -1;
    printf("%d\n", ans);
  }
}
