#pragma GCC optimize ("O3")

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <set>
#include <algorithm>
#include <numeric>
#include <list>
using namespace std;

using QWORD  = uint64_t;
using SQWORD = int64_t;
using DWORD  = uint32_t;
using SDWORD = int32_t;
using WORD   = uint16_t;
using SWORD  = int16_t;
using BYTE   = uint8_t;
using SBYTE  = int8_t;
using DOUBLE = double;
using FLOAT  = float;

#define MIN_SDWORD (-2147483648)
#define MAX_SDWORD (2147483647)
#define MIN_SBYTE (-128)
#define MAX_SBYTE (127)

#define MIN_SQWORD (0x8000000000000000)
#define MAX_SQWORD (0x7FFFFFFFFFFFFFFF)

#define MAX_QWORD  (0xFFFFFFFFFFFFFFFF)
#define MAX_DWORD  (0xFFFFFFFF)
#define MAX_WORD   (0xFFFF)
#define MAX_BYTE   (0xFF)


#define ArrayLength(a)  (sizeof(a) / sizeof(a[0]))

static inline QWORD MAX(QWORD a, QWORD b) { return a > b ? a : b; }
static inline DWORD MAX(DWORD a, DWORD b) { return a > b ? a : b; }
static inline SDWORD MAX(SDWORD a, SDWORD b) { return a > b ? a : b; }
static inline QWORD MIN(QWORD a, QWORD b) { return a < b ? a : b; }
static inline DWORD MIN(DWORD a, DWORD b) { return a < b ? a : b; }
static inline SDWORD MIN(SDWORD a, SDWORD b) { return a < b ? a : b; }

#define BYTE_BITS   (8)
#define WORD_BITS   (16)
#define DWORD_BITS  (32)
#define QWORD_BITS  (64)

using M_BOOL = bool;
#define M_TRUE (true)
#define M_FALSE (false)
#define DIVISOR (1000000007)

static inline void inputString(char *pcStr)
{
    char *pcCur = pcStr;
    for (;;) {
        char c = getchar();
        if (('\n' == c) || (EOF == c)) {
            break;
        }
        *pcCur = c;
        pcCur++;
    }
    *pcCur = '\0';
}


static inline SQWORD inputSQWORD(void)
{
    SQWORD sqNumber = 0;
    SQWORD sqMultiplier = 1;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                sqMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            sqNumber *= 10LL;
            sqNumber += (SQWORD)(c - '0');
            bRead = M_TRUE;
        } else {
            if (bRead) {
                return sqNumber * sqMultiplier;
            }
        }
    }
}


static inline SDWORD inputSDWORD(void)
{
    SDWORD lNumber = 0;
    SDWORD lMultiplier = 1;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                lMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            lNumber *= 10;
            lNumber += (c - '0');
            bRead = M_TRUE;
        } else {
            if (bRead) {
                return lNumber * lMultiplier;
            }
        }
    }
}

static inline DOUBLE inputFP(void)
{
    DOUBLE dInt = 0.0;
    DOUBLE dFrac = 0.0;
    DOUBLE dMultiplier = 1.0;
    DWORD dwFpCnt = 0;
    DOUBLE *pdCur = &dInt;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                dMultiplier = -1;
            }
        }
        if ('.' == c) {
            pdCur = &dFrac;
        } else if (('0' <= c) && (c <= '9')) {
            (*pdCur) *= 10;
            (*pdCur) += (DOUBLE)(c - '0');
            bRead = M_TRUE;
            if (pdCur == &dFrac) {
                dwFpCnt++;
            }
        } else {
            if (bRead) {
                return dMultiplier * (dInt + dFrac / (pow((DOUBLE)10.0 , (DOUBLE)dwFpCnt)));
            }
        }
    }
}


/**
 *  mod による操作ライブラリ
 */

#define ANS_MOD (1000000007LL)
 
static SQWORD addMod(SQWORD x, SQWORD y)
{ 
    return (x + y) % ANS_MOD;
}
 
static SQWORD subMod(SQWORD x, SQWORD y)
{
    return (x - y + ANS_MOD) % ANS_MOD;
}
 
static SQWORD mulMod(SQWORD x, SQWORD y) 
{
    return (x * y) % ANS_MOD;
}
 
static SQWORD powMod(SQWORD x, SQWORD e) {
    SQWORD v = 1;
    for (; e; x = mulMod(x, x), e >>= 1) {
        if (e & 1) {
            v = mulMod(v, x);
        }
    }
    return v;
}
 
static SQWORD divMod(SQWORD x, SQWORD y)
{
    return mulMod(x, powMod(y, ANS_MOD - 2));
}
 
 
static SQWORD combMod(SQWORD n, SQWORD k)
{
    SQWORD v=1;
    for(SQWORD i=1; i<=k; i++) {
        v = divMod(mulMod(v, n-i+1),i);
    } 
    return v;
}

/*----------------------------------------------*/

#define MAX_STRING  (2000)

int main(void)
{
    SQWORD sqInput_N = inputSQWORD();
    SQWORD sqInput_M = inputSQWORD();

    vector<SQWORD> vecsqS;
    vector<SQWORD> vecsqT;

    vecsqS.emplace_back(0);
    for (SQWORD sqIdx = 0; sqIdx < sqInput_N; sqIdx++) {
        SQWORD sqS = inputSQWORD();
        vecsqS.emplace_back(sqS);
    }
    vecsqT.emplace_back(0);
    for (SQWORD sqIdx = 0; sqIdx < sqInput_M; sqIdx++) {
        SQWORD sqT = inputSQWORD();
        vecsqT.emplace_back(sqT);
    }

    /*
    *   dp[i][j] = sum(dp[m][n])  (if A[i] = A[j], 1<m< i, 1<n<j )
    *   dp[i][j] = 0              (if A[i] <> A[j])
    */
    static SQWORD s_aasqDpTbl[MAX_STRING + 1][MAX_STRING + 1];
    static SQWORD s_aasqSumTblST[MAX_STRING + 1][MAX_STRING + 1];
    
    SQWORD sqMaxI = 0;
    SQWORD sqMaxJ = 0;
    for (SQWORD sqIdxI = 0; sqIdxI <= sqInput_N; sqIdxI++) {
        for (SQWORD sqIdxJ = 0; sqIdxJ <= sqInput_M; sqIdxJ++) {
            if ((0 == sqIdxI) || (0 == sqIdxJ)) {
                s_aasqDpTbl[sqIdxI][sqIdxJ] = 1;
                s_aasqSumTblST[sqIdxI][sqIdxJ] = 1;
            } else {
                SQWORD sqDp;
                if (vecsqS[sqIdxI] == vecsqT[sqIdxJ]) {
                    sqDp = s_aasqSumTblST[sqIdxI - 1][sqIdxJ - 1];
                } else {
                    sqDp = 0;
                }
                s_aasqDpTbl[sqIdxI][sqIdxJ] = sqDp;
                SQWORD sqNextSum = 0;
                sqNextSum = addMod(sqNextSum, s_aasqSumTblST[sqIdxI-1][sqIdxJ]);
                sqNextSum = addMod(sqNextSum, s_aasqSumTblST[sqIdxI][sqIdxJ-1]);
                sqNextSum = subMod(sqNextSum, s_aasqSumTblST[sqIdxI-1][sqIdxJ-1]);
                sqNextSum = addMod(sqNextSum, sqDp);
                s_aasqSumTblST[sqIdxI][sqIdxJ] = sqNextSum;
            }
        }
    }
    printf("%lld\n", s_aasqSumTblST[sqInput_N][sqInput_M]);

    return 0;
}

Measured memory_bytes: 31616