#include <bits/stdc++.h>
using namespace std;
const int maxn = 500010;
int n, m;
char a[maxn], b[maxn];
char s[maxn * 2], c[maxn * 3];
int z[maxn * 3];
int lcp[maxn];
int lcs[maxn];
void z_init(int len) {
  int l = 1, r = 1;
  z[1] = len;
  for (int i = 2; i <= len; i++) {
    if (i > r) {
      l = i;
      r = i;
      while (r <= len && c[r - i + 1] == c[r]) r++;
      z[i] = r - l;
      r--;
    } else {
      int k = i - l + 1;
      if (z[k] < r - i + 1)
        z[i] = z[k];
      else {
        l = i;
        while (r <= len && c[r - i + 1] == c[r]) r++;
        z[i] = r - l;
        r--;
      }
    }
  }
}
void init() {
  for (int i = 1; i <= m; i++) c[i] = s[i];
  c[m + 1] = '#';
  for (int i = 1; i <= n; i++) c[m + 1 + i] = a[i];
  c[n + m + 2] = '\0';
  z_init(n + m + 1);
  for (int i = 1; i <= n; i++) lcp[i] = z[m + 1 + i];
  for (int i = 1; i <= m; i++) c[i] = s[m + 1 - i];
  c[m + 1] = '#';
  for (int i = 1; i <= n; i++) c[m + 1 + i] = b[n + 1 - i];
  c[n + m + 2] = '\0';
  z_init(n + m + 1);
  for (int i = 1; i <= n; i++) lcs[i] = z[m + 1 + n + 1 - i];
}
long long cnt[maxn * 2], sum[maxn * 2];
int lowbit(int x) { return x & (-x); }
void add(int v) {
  int x = v;
  while (x <= n) sum[x] += v, cnt[x]++, x += lowbit(x);
}
void sub(int v) {
  int x = v;
  while (x <= n) sum[x] -= v, cnt[x]--, x += lowbit(x);
}
long long get_sum(int x) {
  long long res = 0;
  while (x) res += sum[x], x -= lowbit(x);
  return res;
}
long long get_cnt(int x) {
  long long res = 0;
  while (x) res += cnt[x], x -= lowbit(x);
  return res;
}
int main() {
  scanf("%d%d", &n, &m);
  scanf("%s%s%s", a + 1, b + 1, s + 1);
  init();
  long long ans = 0;
  for (int i = 1; i <= min(n, m - 1); i++) add(max(1, m - lcs[i]));
  for (int i = 1, r; i <= n; i++) {
    r = min(m - 1, lcp[i]);
    ans += 1LL * (r + 1) * get_cnt(r) - get_sum(r);
    sub(max(1, m - lcs[i]));
    if (i + m - 1 <= n) add(max(1, m - lcs[i + m - 1]));
  }
  printf("%I64d\n", ans);
}
