#include <bits/stdc++.h>
using namespace std;
const int N = 200000 + 5;
struct Matrix {
  int a[5][5];
  Matrix operator*(const Matrix& ot) {
    Matrix rtn;
    for (int i = 0; i < 5; ++i) {
      for (int j = 0; j < 5; ++j) {
        rtn.a[i][j] = 100000000;
        for (int k = 0; k < 5; ++k) {
          rtn.a[i][j] = min(rtn.a[i][j], a[i][k] + ot.a[k][j]);
        }
      }
    }
    return rtn;
  }
};
struct Node {
  int l, r, rt;
  Matrix m;
} node[N << 2];
char s[N];
void build(int l, int r, int rt) {
  if (l == r) {
    for (int i = 0; i < 5; ++i) {
      for (int j = 0; j < 5; ++j) {
        node[rt].m.a[i][j] = 100000000;
        if (i == j) node[rt].m.a[i][j] = 0;
      }
    }
    if (s[l] == '2') node[rt].m.a[0][0] = 1, node[rt].m.a[0][1] = 0;
    if (s[l] == '0') node[rt].m.a[1][1] = 1, node[rt].m.a[1][2] = 0;
    if (s[l] == '1') node[rt].m.a[2][2] = 1, node[rt].m.a[2][3] = 0;
    if (s[l] == '7') node[rt].m.a[3][3] = 1, node[rt].m.a[3][4] = 0;
    if (s[l] == '6') node[rt].m.a[3][3] = 1, node[rt].m.a[4][4] = 1;
    return;
  }
  int mid = (l + r) >> 1;
  build(l, mid, rt << 1);
  build(mid + 1, r, rt << 1 | 1);
  node[rt].m = node[rt << 1].m * node[rt << 1 | 1].m;
}
Matrix query(int L, int R, int l, int r, int rt) {
  if (L <= l && r <= R) return node[rt].m;
  int mid = (l + r) >> 1;
  Matrix rtn;
  for (int i = 0; i < 5; ++i) {
    for (int j = 0; j < 5; ++j) rtn.a[i][j] = 100000000;
    rtn.a[i][i] = 0;
  }
  if (L <= mid) rtn = rtn * query(L, R, l, mid, rt << 1);
  if (mid < R) rtn = rtn * query(L, R, mid + 1, r, rt << 1 | 1);
  return rtn;
}
void solve() {
  int n, m;
  scanf("%d%d%s", &n, &m, s + 1);
  build(1, n, 1);
  for (; m; --m) {
    int l, r;
    scanf("%d%d", &l, &r);
    Matrix qr = query(l, r, 1, n, 1);
    if (qr.a[0][4] >= 100000000)
      puts("-1");
    else
      printf("%d\n", qr.a[0][4]);
  }
}
int main() {
  solve();
  return 0;
}
