#include <stdio.h>
#include <string.h>
#define N 300000
#define M 10000
#define L 500000
#define N_ (L + 2)
#define A 26
int tt[N_][A], ff_[N_][A], ff[N_], dd[N_], n_;
void build(char **ccc, int m) {
static int qu[N_];
int cnt, l, g, h, a, s, t, e, f;
n_ = 2;
dd[0] = -1, dd[1] = 0;
for (h = 0; h < m; h++) {
l = strlen(ccc[h]);
for (g = 0, s = 1; g < l; g++) {
a = ccc[h][g] - 'a';
if (!tt[s][a])
dd[tt[s][a] = n_++] = g + 1;
s = tt[s][a];
}
}
cnt = 0;
for (a = 0; a < A; a++)
tt[0][a] = 1, ff_[0][a] = 0;
ff[1] = 0, qu[cnt++] = 1;
for (h = 0; h < cnt; h++) {
s = qu[h], e = ff[s];
for (a = 0; a < A; a++) {
t = tt[s][a], f = tt[e][a];
if (t == 0)
tt[s][a] = f, ff_[s][a] = s;
else
ff_[s][a] = ff_[e][a], ff[t] = f, qu[cnt++] = t;
}
}
}
int main() {
static char aa[N + 1], bb[L + 1], *ccc[M], rank[N + 1];
static int rr[N + 1], jj[N + 1], jj_[N + 1], qu[N + 1];
int n, m, q, cnt, h, i, j, a, s, t, lower, upper;
scanf("%d%d", &m, &q);
for (h = 0; h < m; h++) {
scanf("%s", bb);
ccc[h] = strdup(bb);
}
scanf("%s", aa), n = strlen(aa);
build(ccc, m);
for (i = 0, s = 1; i < n; i++) {
a = aa[i] - 'a';
for (t = s; t = ff_[t][a]; t = ff[t])
rr[i - dd[t]] = i;
s = tt[s][a];
}
while (dd[s] >= 0)
rr[n - dd[s]] = n, s = ff[s];
cnt = 0;
for (i = n; i >= 0; i--) {
while (cnt && rr[qu[cnt - 1]] <= rr[i])
cnt--;
qu[cnt++] = i;
lower = -1, upper = cnt - 1;
while (upper - lower > 1) {
h = (lower + upper) / 2;
if (qu[h] <= rr[i])
upper = h;
else
lower = h;
}
jj[i] = qu[upper];
if (i == jj[i])
jj_[i] = jj[i], rank[i] = 0;
else if (rank[jj[i]] == rank[jj_[jj[i]]])
jj_[i] = jj_[jj_[jj[i]]], rank[i] = rank[jj[i]] + 1;
else
jj_[i] = jj[i], rank[i] = 1;
}
while (q--) {
int k;
scanf("%d%d", &i, &j);
k = 1;
while (rr[i] < j) {
if (i == jj[i]) {
k = -1;
break;
}
if (rr[jj_[i]] < j)
k += (1 << rank[i]) - 1, i = jj_[i];
else
k++, i = jj[i];
}
printf("%d\n", k);
}
return 0;
}
