#P1313E. Concatenation with intersection

    ID: 1744 Type: RemoteJudge 2000ms 512MiB Tried: 0 Accepted: 0 Difficulty: (None) Uploaded By: Tags>data structureshashingstringstwo pointers*2700

Concatenation with intersection

No submission language available for this problem.

Description

Vasya had three strings aa, bb and ss, which consist of lowercase English letters. The lengths of strings aa and bb are equal to nn, the length of the string ss is equal to mm.

Vasya decided to choose a substring of the string aa, then choose a substring of the string bb and concatenate them. Formally, he chooses a segment [l1,r1][l_1, r_1] (1l1r1n1 \leq l_1 \leq r_1 \leq n) and a segment [l2,r2][l_2, r_2] (1l2r2n1 \leq l_2 \leq r_2 \leq n), and after concatenation he obtains a string a[l1,r1]+b[l2,r2]=al1al1+1ar1bl2bl2+1br2a[l_1, r_1] + b[l_2, r_2] = a_{l_1} a_{l_1 + 1} \ldots a_{r_1} b_{l_2} b_{l_2 + 1} \ldots b_{r_2}.

Now, Vasya is interested in counting number of ways to choose those segments adhering to the following conditions:

  • segments [l1,r1][l_1, r_1] and [l2,r2][l_2, r_2] have non-empty intersection, i.e. there exists at least one integer xx, such that l1xr1l_1 \leq x \leq r_1 and l2xr2l_2 \leq x \leq r_2;
  • the string a[l1,r1]+b[l2,r2]a[l_1, r_1] + b[l_2, r_2] is equal to the string ss.

The first line contains integers nn and mm (1n500000,2m2n1 \leq n \leq 500\,000, 2 \leq m \leq 2 \cdot n) — the length of strings aa and bb and the length of the string ss.

The next three lines contain strings aa, bb and ss, respectively. The length of the strings aa and bb is nn, while the length of the string ss is mm.

All strings consist of lowercase English letters.

Print one integer — the number of ways to choose a pair of segments, which satisfy Vasya's conditions.

Input

The first line contains integers nn and mm (1n500000,2m2n1 \leq n \leq 500\,000, 2 \leq m \leq 2 \cdot n) — the length of strings aa and bb and the length of the string ss.

The next three lines contain strings aa, bb and ss, respectively. The length of the strings aa and bb is nn, while the length of the string ss is mm.

All strings consist of lowercase English letters.

Output

Print one integer — the number of ways to choose a pair of segments, which satisfy Vasya's conditions.

Samples

Sample Input 1

6 5
aabbaa
baaaab
aaaaa

Sample Output 1

4

Sample Input 2

5 4
azaza
zazaz
azaz

Sample Output 2

11

Sample Input 3

9 12
abcabcabc
xyzxyzxyz
abcabcayzxyz

Sample Output 3

2

Note

Let's list all the pairs of segments that Vasya could choose in the first example:

  1. [2,2][2, 2] and [2,5][2, 5];
  2. [1,2][1, 2] and [2,4][2, 4];
  3. [5,5][5, 5] and [2,5][2, 5];
  4. [5,6][5, 6] and [3,5][3, 5];