/**
	author:  shobonvip
	created: 2025.08.22 21:19:45
**/
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
using namespace std;

//* ATCODER
#include<atcoder/all>
using namespace atcoder;
typedef modint998244353 mint;
//*/

/* BOOST MULTIPRECISION
#include<boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
//*/

typedef long long ll;

#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)
#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)
#define all(v) v.begin(), v.end()

template <typename T> bool chmin(T &a, const T &b) {
	if (a <= b) return false;
	a = b;
	return true;
}

template <typename T> bool chmax(T &a, const T &b) {
	if (a >= b) return false;
	a = b;
	return true;
}

template <typename T> T max(vector<T> &a){
	assert(!a.empty());
	T ret = a[0];
	for (int i=0; i<(int)a.size(); i++) chmax(ret, a[i]);
	return ret;
}

template <typename T> T min(vector<T> &a){
	assert(!a.empty());
	T ret = a[0];
	for (int i=0; i<(int)a.size(); i++) chmin(ret, a[i]);
	return ret;
}

template <typename T> T sum(vector<T> &a){
	T ret = 0;
	for (int i=0; i<(int)a.size(); i++) ret += a[i];
	return ret;
}

struct S {
	int v[3];
};

S e() {
	return {-1,-1,-1};
}
S op(S a, S b) {
	S ret = e();
	vector<int> tar;
	if((int)tar.size()<3&&b.v[0]>=0) tar.push_back(b.v[0]);
	if((int)tar.size()<3&&b.v[1]>=0) tar.push_back(b.v[1]);
	if((int)tar.size()<3&&b.v[2]>=0) tar.push_back(b.v[2]);
	if((int)tar.size()<3&&a.v[0]>=0) tar.push_back(a.v[0]);
	if((int)tar.size()<3&&a.v[1]>=0) tar.push_back(a.v[1]);
	if((int)tar.size()<3&&a.v[2]>=0) tar.push_back(a.v[2]);
	while((int)tar.size()<3) tar.push_back(-1);
	ret.v[0]=tar[0];
	ret.v[1]=tar[1];
	ret.v[2]=tar[2];
	return ret;
};


int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	
	int n,q;
	cin >> n >> q;
	string s; cin >> s;
	vector<int> a(n);
	rep(i,0,n) {
		a[i] = int(s[i] - '0');
	}

	vector<segtree<S,op,e>> segs(10,segtree<S,op,e>(0));
	vector<vector<S>> init(10,vector<S>(n,e()));
	rep(i,0,n){
		init[a[i]][i] = S{i, -1,-1};
	}
	rep(i,1,10) {
		segs[i] = segtree<S,op,e>(init[i]);
	}

	vector<vector<pair<int,int>>> good;
	for(int i=0;i<1000;i+=8){
		vector<int>a;
		int x=i;
		bool mode=1;
		rep(j,0,3){
			a.push_back(x%10);
			if(x%10==0)mode=0;
			x/=10;
		}
		if(!mode)continue;
		reverse(all(a));
		vector<int>segi(10);
		vector<pair<int,int>>ret(3);
		rrep(i,0,3){
			ret[i]=pair(a[i],segi[a[i]]);
			segi[a[i]]++;
		}
		good.push_back(ret);
		//cout<<i<<endl;
	}

	while(q--) {
		int l,r;cin>>l>>r;
		l--;
		if(r-l==1){
			if(a[l]==8)cout<<0<<'\n';
			else cout<<-1<<'\n';
			continue;
		}
		if(r-l==2){
			if((a[l]*10+a[l+1])%8==0)cout<<0<<'\n';
			else if((a[l+1]*10+a[l])%8==0)cout<<1<<'\n';
			else cout<<-1<<'\n';
			continue;
		}

		int ans=1e9;
		vector<S> vals(10);
		rep(i,1,10){
			vals[i]=segs[i].prod(l,r);
		}
		rep(num,0,(int)good.size()){
			vector<int> gl(3);
			bool mode=1;
			rrep(i,0,3){
				gl[i]=vals[good[num][i].first].v[good[num][i].second];
				if(gl[i]==-1){
					mode=0;
					break;
				}
			}
			if(!mode)continue;
			int tar=3*r-6-gl[0]-gl[1]-gl[2];
			tar+=int(gl[0]>gl[1]);
			tar+=int(gl[0]>gl[2]);
			tar+=int(gl[1]>gl[2]);
			chmin(ans,tar);
		}
		if(ans==(int)1e9)cout<<-1<<'\n';
		else cout<<ans<<'\n';
	}
}