#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cerr << name << ": " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << ": " << arg1 << " |";
  __f(comma + 1, args...);
}
const int INF = 1 << 29;
const int MOD = 1e9 + 7;
const int N = 2e5 + 10;
const int K = 5;
char s[N];
struct Mat {
  int a[5][5];
};
Mat operator+(const Mat& a, const Mat& b) {
  Mat ret;
  for (int i = 0; i < K; ++i) {
    for (int j = 0; j < K; ++j) {
      ret.a[i][j] = INF;
      for (int k = 0; k < K; ++k) {
        ret.a[i][j] = min(ret.a[i][j], a.a[i][k] + b.a[k][j]);
      }
    }
  }
  return ret;
}
struct Node {
  int a, b;
  Node *left, *right;
  Mat sum;
};
Node pool[N << 1], *last;
Node* build(int a, int b) {
  Node* cur = last++;
  cur->a = a;
  cur->b = b;
  if (a + 1 == b) {
    for (int i = 0; i < K; ++i) {
      for (int j = 0; j < K; ++j) {
        cur->sum.a[i][j] = INF;
      }
      cur->sum.a[i][i] = 0;
    }
    if (s[a] == '2') {
      cur->sum.a[0][0] = 1;
      cur->sum.a[0][1] = 0;
    } else if (s[a] == '0') {
      cur->sum.a[1][1] = 1;
      cur->sum.a[1][2] = 0;
    } else if (s[a] == '1') {
      cur->sum.a[2][2] = 1;
      cur->sum.a[2][3] = 0;
    } else if (s[a] == '6') {
      cur->sum.a[3][3] = 1;
      cur->sum.a[4][4] = 1;
    } else if (s[a] == '7') {
      cur->sum.a[3][3] = 1;
      cur->sum.a[3][4] = 0;
    }
    return cur;
  }
  cur->left = build(a, (a + b) / 2);
  cur->right = build((a + b) / 2, b);
  cur->sum = cur->left->sum + cur->right->sum;
  return cur;
}
int A, B;
Mat query(Node* cur) {
  if (cur->a >= A && cur->b <= B) {
    return cur->sum;
  }
  Mat ret;
  for (int i = 0; i < K; ++i) {
    for (int j = 0; j < K; ++j) {
      ret.a[i][j] = INF;
    }
    ret.a[i][i] = 0;
  }
  if ((cur->a + cur->b) / 2 > A) ret = ret + query(cur->left);
  if ((cur->a + cur->b) / 2 < B) ret = ret + query(cur->right);
  return ret;
}
void debug(Node* cur, int dep) {
  if (cur == nullptr) return;
  for (int i = 0; i < dep; ++i) putchar(' ');
  printf("[%d,%d):\n", cur->a, cur->b);
  for (int i = 0; i < K; ++i) {
    for (int j = 0; j < K; ++j) {
      int val = cur->sum.a[i][j];
      if (val == INF) val = -1;
      printf("%d ", val);
    }
    puts("");
  }
  debug(cur->left, dep + 1);
  debug(cur->right, dep + 1);
}
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  scanf("%s", s);
  last = pool;
  Node* root = build(0, n);
  while (m--) {
    scanf("%d%d", &A, &B);
    --A;
    int ret = query(root).a[0][4];
    if (ret == INF) ret = -1;
    printf("%d\n", ret);
  }
  return 0;
}
