#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n) - 1; i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r) - 1;i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
int inv(vector<int>v) {
	int ret = 0;
	rep(i, v.size())rep(j, i)if (v[j] > v[i])ret++;
	return ret;
}

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int n, q; cin >> n >> q;
	string s; cin >> s;
	vector prev(3, vector(10, vector<int>(n, -1)));
	rep(i, n) {
		int num = s[i] - '0';
		rep2(j, 1, 10) {
			if (num == j) {
				prev[0][j][i] = i;
				if (i != 0) {
					rep(k, 2)prev[k + 1][j][i] = prev[k][j][i - 1];
				}
			}
			else {
				if (i != 0) {
					rep(k, 3)prev[k][j][i] = prev[k][j][i - 1];
				}
			}
		}
	}
	vector<int>mod8;
	rep(i, 1000) {
		if (i % 8)continue;
		string s = to_string(1000 + i);
		bool chk = false;
		rep(i, s.size())if (s[i] == '0')chk = true;
		if (chk)continue;
		mod8.push_back(i);
	}

	while (q--) {
		int l, r; cin >> l >> r;
		l--;
		if (r - l == 1) {
			int ans = -1;
			if (s[l] == '8')ans = 0;
			cout << ans << endl;
		}
		else if (r - l == 2) {
			int n0 = s[l] - '0';
			int n1 = s[l + 1] - '0';
			int ans = -1;
			if ((n0 * 10 + n1) % 8 == 0)ans = 0;
			else if ((n1 * 10 + n0) % 8 == 0)ans = 1;
			cout << ans << endl;
		}
		else {
			int ans = INF;
			for (auto tar : mod8) {
				int n0 = tar / 100;
				int n1 = (tar / 10) % 10;
				int n2 = tar % 10;
				vector<int>use(10);
				int i2 = prev[use[n2]][n2][r - 1];
				use[n2]++;
				int i1 = prev[use[n1]][n1][r - 1];
				use[n1]++;
				int i0 = prev[use[n0]][n0][r - 1];
				use[n0]++;
				if (i0 < l || i1 < l || i2 < l)continue;
				int val = 3 * r - 6 - i0 - i1 - i2 + inv({ i0,i1,i2 });
				chmin(ans, val);
			}
			if (ans == INF)ans = -1;
			cout << ans << endl;
		}
	}
	return 0;
}