#include <bits/stdc++.h>
using namespace std;
char a[500001 + 10], b[500001 + 10], s[(500001 << 1) + 10];
int n, m;
struct BIT {
  long long c[500001 << 1];
  long long query(int x) {
    if (x <= 0) return 0;
    long long ans = 0;
    for (int i = x; i; i -= (i & -i)) ans += c[i];
    return ans;
  }
  void add(int x, long long p) {
    if (x <= 0) x = 1;
    for (int i = x; i <= 1000000; i += (i & -i)) c[i] += p;
  }
} b1, b2;
int za[500001 * 3], zb[500001 * 3];
char mod[500001 * 3];
void zfunc(char *s, int n, int *z) {
  int l = 0, r = 0;
  z[1] = n;
  int pt;
  for (int i = 2; i <= n; ++i) {
    if (r < i) {
      for (pt = i; pt <= n && s[pt] == s[pt - i + 1]; ++pt)
        ;
      --pt;
      z[i] = pt - i + 1;
      if (z[i]) l = i, r = pt;
    } else {
      int b = r - i + 1, i_ = i - l + 1;
      if (z[i_] < b)
        z[i] = z[i_];
      else {
        for (pt = r + 1; pt <= n && s[pt] == s[pt - i + 1]; ++pt)
          ;
        --pt;
        z[i] = pt - i + 1;
        l = i, r = pt;
      }
    }
  }
}
int main() {
  scanf("%d%d", &n, &m);
  scanf("%s%s%s", a + 1, b + 1, s + 1);
  memcpy(mod + 1, s + 1, m - 1);
  mod[m] = '$';
  memcpy(mod + m + 1, a + 1, n);
  zfunc(mod, n + m, za);
  for (int i = 1; i <= n; ++i) za[i] = za[i + m];
  reverse(s + 1, s + 1 + m);
  reverse(b + 1, b + 1 + n);
  memcpy(mod + 1, s + 1, m - 1);
  mod[m] = '$';
  memcpy(mod + m + 1, b + 1, n);
  zfunc(mod, n + m, zb);
  for (int i = 1; i <= n; ++i) zb[i] = zb[i + m];
  reverse(zb + 1, zb + 1 + n);
  int cur = 1;
  long long ans = 0;
  for (int i = 1; i <= n; ++i) {
    while (cur <= min(i + m - 2, n))
      b1.add(m - 1 - zb[cur], 1), b2.add(m - 1 - zb[cur], zb[cur]), ++cur;
    ans += 1ll * b1.query(za[i]) * (za[i] - m + 1) + b2.query(za[i]);
    b1.add(m - 1 - zb[i], -1), b2.add(m - 1 - zb[i], -zb[i]);
  }
  printf("%lld\n", ans);
  return 0;
}
