/*
in the name of god
*/
//#pragma GCC optimize("Ofast,O3,unroll-loops")
//#pragma GCC target("avx,avx2,fma")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4.1,sse4.2,sse4a,avx,avx2,popcnt,tune=native")
#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> pii;
typedef pair<long long ,long long> pll;
typedef long long ll ;
#define File freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
#define all(V) V.begin(),V.end()
#define setprec(x) fixed << setprecision(x)
#define Mp(a,b) make_pair(a,b)
#define len(V) (int)(V.size())
#define sep ' '
#define endl '\n'
#define pb push_back
#define fi first
#define sec second
#define popcount(x) __builtin_popcount(x)
#define lid u<<1
#define rid (lid)|1
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll N = 5e5 + 10,SQ=320,LOG=22;
const ll inf = 2e9 , MD = 1e9 + 7;
inline ll md(ll x){ x %= MD; return (x < 0 ? x + MD : x);}
int n , m ;
int P[2];
int Inv(int x){
return (x <= 1 ? 1 : md(-(MD/x)*Inv(MD%x)));
}
int pw[N][2],inv[N][2];
vector<pii> Hash[N];
string s;
int l;
int f[N];
int ps[N][2];
pii mx[N][LOG];
int dp[N][LOG];
inline pii gethash(int l,int r){
pii ans;
for(int j = 0;j < 2;j++){
int x = ps[r][j];
if(l) x = md(x - ps[l-1][j]);
x = md(x * inv[l][j]);
if(j == 0) ans.fi = x;
else ans.sec = x;
}
return ans;
}
inline pii get(int l,int r){
int ln = r - l + 1;
ln = __lg(ln);
// cout << ln << sep << mx[l][ln].fi << sep << r + 1 - (1<<ln) << sep << mx[r + 1 - (1<<ln)][ln].fi << endl;
return max(mx[l][ln],mx[r + 1 - (1<<ln)][ln]);
}
bool check(int l,int r){
pii h = gethash(l,r);
int x = lower_bound(all(Hash[r-l+1]),h) - Hash[r-l+1].begin();
if(x < len(Hash[r-l+1]) && Hash[r-l+1][x] == h) return 1;
return 0;
}
int ask(int l,int r){
int tmp = l;
int cost = 0;
for(int j = LOG-1;j >= 0;j--){
if(dp[l][j] < r){
cost += (1<<j);
l = get(tmp,dp[l][j]).sec;
}
}
if(dp[l][0] >= r) return cost + 1;
return -1;
}
bool isprime(int x){
if(x == 1) return 0;
for(int j = 2;j<x;j++){
if(x%j == 0) return 0;
}
return 1;
}
int32_t main() {
ios_base::sync_with_stdio(false);cout.tie(0);cin.tie(0);
cin >> n >> m ;
rng.seed(n^m);
for(int j = 0;j < 2;j++){
P[j] = rng()%1000 + 100;
while(!isprime(P[j])) P[j]++;
}
for(int j = 0 ;j < 2;j++) pw[0][j] = inv[0][j] = 1;
for(int i =1 ;i < N;i++){
for(int j = 0 ;j < 2;j++){
pw[i][j] = md(pw[i-1][j] * P[j]);
}
}
for(int j = 0; j <2;j++) inv[1][j] = Inv(P[j]);
for(int i =2 ;i < N;i++) {
for(int j = 0;j < 2 ;j++){
inv[i][j] = md(inv[i-1][j] * inv[1][j]);
}
}
for(int i = 1 ;i <= n;i++){
string s;
cin >> s;
int hs[2] = {0,0};
for(int j = 0; j < len(s);j++){
for(int r = 0;r < 2;r++){
hs[r] = md(hs[r] + md(pw[j][r] * (s[j] - 'a')));
}
Hash[j+1].pb(Mp(hs[0],hs[1]));
}
}
for(int i = 1;i < N;i++) sort(all(Hash[i]));
cin >> s;
l = len(s);
for(int j = 0; j < 2;j++) ps[0][j] = (s[0] - 'a');
for(int i = 1;i < l;i++){
for(int j = 0; j < 2;j++){
ps[i][j] = md(ps[i-1][j] + md((s[i] - 'a') * pw[i][j]));
}
}
for(int i = 0; i < l;i++){
int dw = i-1,up = l;
while(up-dw>1){
int mid = (up + dw)>>1;
if(check(i,mid)) dw = mid;
else up = mid;
}
f[i] = up;
}
for(int i = l-1 ;i >= 0;i--){
mx[i][0] = {f[i],i};
for(int j =1 ;j < LOG && i + (1<<j) - 1 < l;j++){
mx[i][j] = max(mx[i][j-1],mx[i+(1<<(j-1))][j-1]);
}
}
for(int i = l-1; i >= 0;i--){
dp[i][0] = f[i];
for(int j = 1;j < LOG;j++){
dp[i][j] = dp[i][j-1];
if(dp[i][j] < l){
int R = get(i,dp[i][j]).sec;
dp[i][j] = dp[R][j-1];
}
}
}
while(m--){
int l,r;
cin >> l >> r;
cout << ask(l,r) << endl;
}
return 0;
}
