#include <bits/stdc++.h>
//#define int ll
#define MAX 1000001
#define INF INT_MAX
#define MOD 1000000007
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ins insert
#define ff first
#define ss second
#define all(a) a.begin(),a.end()
#define lb(a,b) lower_bound(all(a),b)
#define ub(a,b) upper_bound(all(a),b)
#define sortv(a) sort(all(a))
#define outputar(a,b){\
for(int i=0;i<b;i++){\
cout << a[i] << " ";\
}\
cout << endl;\
}
#define outputvec(a){\
for(auto x:a){\
cout << (int)x << " ";\
}\
cout << endl;\
}
#define reset(a,n,v){\
for(int i=0;i<n;i++){\
a[i]=v;\
}\
}
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef tuple<ll,ll,ll> tll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef double db;
typedef long double ldb;
inline void USACO(string filename){
freopen((filename+".in").c_str(),"r",stdin);
freopen((filename+".out").c_str(),"w",stdout);
}
int n,q,t=1,m,k,x,y,z,x2,y2,z2,a[MAX],b[MAX],d[MAX];
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
string s[MAX],str[MAX];
//int e[1001][1001];
string s1,s2,s3;
const int mod = 998244353;
int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};
int cost[501][501],can[501][501];
void solve(){
cin >> n >> q;
for(int i=0;i<n;i++){
cin >> s[i];
}
cin >> s1;
m=(int)s1.size();
for(int i=0;i<m;i++){
for(int j=0;j<n;j++){
k=(int)s[j].size();
for(z=0;z<k;z++){
if(s[j][z]!=s1[i+z]){
break;
}
can[i][i+z]=1;
}
}
}
for(int i=0;i<m;i++){
for(int j=0;j<m;j++){
cost[i][j]=INF;
}
}
for(int i=0;i<m;i++){
for(int j=i;j<m;j++){
if(can[i][j]){
cost[i][j]=1;
if(i-1>=0){
for(int z=0;z<=i-1;z++){
if(cost[z][i-1]!=INF){
cost[z][j]=min(cost[z][j],cost[z][i-1]+1);
}
}
}
}
}
}
for(int i=0;i<q;i++){
cin >> x >> y;
if(cost[x][y-1]==INF){
cout << -1 << "\n";
}
else{
cout << cost[x][y-1] << "\n";
}
}
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
//freopen("input13.txt","r",stdin);
//cin >> t;
ll cnt1=1;
while(t--){
solve();
cnt1++;
}
}
