#include <bits/stdc++.h>
using namespace std;
inline char gc() {
  static char buf[1 << 16], *S, *T;
  if (S == T) {
    T = (S = buf) + fread(buf, 1, 1 << 16, stdin);
    if (T == S) return EOF;
  }
  return *S++;
}
inline int read() {
  int x = 0, f = 1;
  char ch = gc();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = gc();
  }
  while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = gc();
  return x * f;
}
char s[200010];
inline void get_S() {
  char ch = gc();
  int tot = 0;
  while (ch < '0' || ch > '9') ch = gc();
  while (ch >= '0' && ch <= '9') s[++tot] = ch, ch = gc();
}
int n, m;
struct node {
  int a[5][5];
  int* operator[](int x) { return a[x]; }
  inline void init() { memset(a, 0x3f3f3f3f, sizeof(a)); }
  friend node operator+(node a, node b) {
    node res;
    res.init();
    for (int i = 0; i < 5; ++i)
      for (int j = 0; j < 5; ++j)
        for (int k = 0; k < 5; ++k)
          res[i][j] = min(res[i][j], a[i][k] + b[k][j]);
    return res;
  }
} tr[200010 << 2];
inline void build(int p, int l, int r) {
  if (l == r) {
    tr[p].init();
    for (int i = 0; i < 5; ++i) tr[p][i][i] = 0;
    if (s[l] == '2') {
      tr[p][0][1] = 0;
      tr[p][0][0] = 1;
      return;
    }
    if (s[l] == '0') {
      tr[p][1][2] = 0;
      tr[p][1][1] = 1;
      return;
    }
    if (s[l] == '1') {
      tr[p][2][3] = 0;
      tr[p][2][2] = 1;
      return;
    }
    if (s[l] == '6') {
      tr[p][3][3] = 1;
      tr[p][4][4] = 1;
      return;
    }
    if (s[l] == '7') {
      tr[p][3][4] = 0;
      tr[p][3][3] = 0;
      return;
    }
    return;
  }
  int mid = l + r >> 1;
  build(p << 1, l, mid);
  build(p << 1 | 1, mid + 1, r);
  tr[p] = tr[p << 1] + tr[p << 1 | 1];
}
inline node ask(int p, int l, int r, int x, int y) {
  if (x == l && r == y) return tr[p];
  int mid = l + r >> 1;
  if (y <= mid) return ask(p << 1, l, mid, x, y);
  if (x > mid) return ask(p << 1 | 1, mid + 1, r, x, y);
  return ask(p << 1, l, mid, x, mid) + ask(p << 1 | 1, mid + 1, r, mid + 1, y);
}
int main() {
  n = read();
  m = read();
  get_S();
  build(1, 1, n);
  while (m--) {
    int x = read(), y = read();
    int res = ask(1, 1, n, x, y).a[0][4];
    if (res == 0x3f3f3f3f)
      puts("-1");
    else
      printf("%d\n", res);
  }
  return 0;
}
