#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 5;
string a, b, s;
long long sum[2 * N];
int cnt[2 * N];
int n, m;
vector<int> Zfunc(string s, string t) {
  string str = s + '#' + t;
  vector<int> z(str.size());
  for (int i = 1, l = 0, r = 0; i < (int)str.size(); i++) {
    int &res = z[i];
    if (i <= r) res = min(z[i - l], r - i);
    while (i + res < (int)str.size() && str[i + res] == str[res]) res++;
    if (i + res >= r) {
      l = i;
      r = i + res;
    }
  }
  reverse(z.begin(), z.end());
  while (z.size() > t.size()) z.pop_back();
  reverse(z.begin(), z.end());
  return z;
}
void update(int val, int num) {
  for (int pos = val; pos <= m; pos += pos & -pos)
    cnt[pos] += num, sum[pos] += num * val;
}
pair<int, long long> getsum(int pos) {
  pair<int, long long> res = make_pair(0, 0);
  for (; pos > 0; pos -= pos & -pos)
    res.first += cnt[pos], res.second += sum[pos];
  return res;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m;
  cin >> a >> b >> s;
  vector<int> f = Zfunc(s, a);
  reverse(b.begin(), b.end());
  reverse(s.begin(), s.end());
  vector<int> g = Zfunc(s, b);
  reverse(g.begin(), g.end());
  for (int i = 0; i < m - 1; i++)
    if (g[i]) update(g[i], 1);
  for (int &x : f)
    if (x == m) x--;
  for (int &x : g)
    if (x == m) x--;
  long long ans = 0;
  for (int i = 0; i < n; i++) {
    if (f[i]) {
      auto r = getsum(m);
      auto l = (f[i] < m) ? getsum(m - f[i] - 1) : make_pair(0, 0LL);
      ans +=
          r.second - l.second - (long long)(r.first - l.first) * (m - f[i] - 1);
    }
    if (g[i]) update(g[i], -1);
    if (i + m - 1 < n && g[i + m - 1]) update(g[i + m - 1], 1);
  }
  cout << ans;
  return 0;
}
