#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
struct node {
  int f[5][5];
} tr[200005 << 2];
int n, m, a[200005];
node pushup(node x, node y) {
  node ans;
  for (int k = 0; k <= 4; k++) {
    for (int j = 0; j <= 4; j++) {
      if (k == j)
        ans.f[k][j] = 0;
      else
        ans.f[k][j] = inf;
    }
  }
  for (int k = 0; k <= 4; k++) ans.f[k][k] = inf;
  for (int i = 0; i <= 4; ++i)
    for (int j = 0; j <= 4; ++j)
      for (int k = 0; k <= 4; ++k)
        ans.f[i][j] = min(ans.f[i][j], x.f[i][k] + y.f[k][j]);
  return ans;
}
void build(int i, int l, int r) {
  if (l == r) {
    for (int k = 0; k <= 4; k++) {
      for (int j = 0; j <= 4; j++) {
        if (k == j)
          tr[i].f[k][j] = 0;
        else
          tr[i].f[k][j] = inf;
      }
    }
    if (a[l] == -1) {
      for (int k = 0; k <= 4; k++) tr[i].f[k][k] = inf;
    } else if (a[l] == 2) {
      tr[i].f[0][0] = 1;
      tr[i].f[0][1] = 0;
    } else if (a[l] == 0) {
      tr[i].f[1][1] = 1;
      tr[i].f[1][2] = 0;
    } else if (a[l] == 1) {
      tr[i].f[2][2] = 1;
      tr[i].f[2][3] = 0;
    } else if (a[l] == 7) {
      tr[i].f[3][3] = 1;
      tr[i].f[3][4] = 0;
    } else if (a[l] == 6) {
      tr[i].f[3][3] = 1;
      tr[i].f[4][4] = 1;
    }
    return;
  }
  int mid = l + r >> 1;
  build(i * 2, l, mid);
  build(i * 2 + 1, mid + 1, r);
  tr[i] = pushup(tr[i * 2], tr[i * 2 + 1]);
}
node query(int i, int l, int r, int x, int y) {
  if (x <= l && r <= y) {
    return tr[i];
  }
  int mid = l + r >> 1;
  if (y <= mid) {
    return query(i * 2, l, mid, x, y);
  }
  if (x > mid) {
    return query(i * 2 + 1, mid + 1, r, x, y);
  }
  return pushup(query(i * 2, l, mid, x, mid),
                query(i * 2 + 1, mid + 1, r, mid + 1, y));
}
char s[200005];
int main() {
  scanf("%d%d", &n, &m);
  scanf("%s", s + 1);
  for (int i = 1; i <= n; ++i) a[i] = s[i] - '0';
  build(1, 1, n);
  while (m--) {
    int x, y;
    scanf("%d%d", &x, &y);
    node ans = query(1, 1, n, x, y);
    if (ans.f[0][4] != inf) {
      printf("%d\n", ans.f[0][4]);
    } else {
      printf("-1\n");
    }
  }
  return 0;
}
