#include <bits/stdc++.h>
using namespace std;
int v[800005][6][6];
int n, q;
char s[200005];
void init(int x, int b, int e) {
  if (b == e) {
    for (int i = 0; i < 6; i++)
      for (int j = 0; j < 6; j++) v[x][i][j] = 1000000000;
    for (int i = 0; i < 6; i++) v[x][i][i] = 0;
    if (s[b] == '2')
      v[x][0][1] = 0, v[x][0][0] = 1;
    else if (s[b] == '0')
      v[x][1][2] = 0, v[x][1][1] = 1;
    else if (s[b] == '1')
      v[x][2][3] = 0, v[x][2][2] = 1;
    else if (s[b] == '7')
      v[x][3][4] = 0, v[x][3][3] = 1;
    else if (s[b] == '6')
      v[x][3][5] = v[x][4][5] = 0, v[x][3][3] = v[x][4][4] = 1;
  } else {
    int l = x * 2, r = x * 2 + 1;
    init(l, b, (((b) + (e)) >> 1));
    init(r, (((b) + (e)) >> 1) + 1, e);
    for (int i = 0; i < 6; i++)
      for (int j = 0; j < 6; j++) v[x][i][j] = 1000000000;
    for (int k = 0; k < 6; k++)
      for (int i = 0; i < 6; i++)
        for (int j = 0; j < 6; j++)
          v[x][i][j] = min(v[x][i][j], v[l][i][k] + v[r][k][j]);
  }
}
struct mat {
  int v[6][6];
  mat() {
    for (int i = 0; i < 6; i++)
      for (int j = 0; j < 6; j++) v[i][j] = 1000000000;
  }
};
mat merge(mat a, mat b) {
  mat c;
  for (int k = 0; k < 6; k++)
    for (int i = 0; i < 6; i++)
      for (int j = 0; j < 6; j++)
        c.v[i][j] = min(c.v[i][j], a.v[i][k] + b.v[k][j]);
  return c;
}
mat query(int x, int b, int e, int qb, int qe) {
  if (b > qe || e < qb) return mat();
  if (b >= qb && e <= qe) {
    mat c;
    for (int i = 0; i < 6; i++)
      for (int j = 0; j < 6; j++) c.v[i][j] = v[x][i][j];
    return c;
  } else {
    int m = (((b) + (e)) >> 1);
    if (qe <= m)
      return query(x * 2, b, (((b) + (e)) >> 1), qb, qe);
    else if (qb > m)
      return query(x * 2 + 1, (((b) + (e)) >> 1) + 1, e, qb, qe);
    else
      return merge(query(x * 2, b, (((b) + (e)) >> 1), qb, qe),
                   query(x * 2 + 1, (((b) + (e)) >> 1) + 1, e, qb, qe));
  }
}
int main() {
  scanf("%d%d%s", &n, &q, s);
  int x, y;
  init(1, 0, n - 1);
  while (q--) {
    scanf("%d%d", &x, &y);
    --x, --y;
    mat c = query(1, 0, n - 1, x, y);
    printf("%d\n", (c.v[0][4] >= 1000000000) ? -1 : c.v[0][4]);
  }
}
