#include<bits/stdc++.h>
using namespace std;
int read()
{
    char s;
    int k=0,base=1;
    while((s=getchar())!='-'&&s!=EOF&&!(s>='0'&&s<='9'));
    if(s==EOF)exit(0);
    if(s=='-')base=-1,s=getchar();
    while(s>='0'&&s<='9')
    {
        k=k*10+(s-'0');
        s=getchar();
    }
    return k*base;
}
void write(int x)
{
    if(x<0)
    {
        putchar('-');
        write(-x);
    }
    else
    {
        if(x/10)write(x/10);
        putchar(x%10+'0');
    }
}
int n,m;
char a[510],b[510];
int f[5][510][510],t;//滚动数组
inline void add(int A,int &B)
{
    B+=A;
    if (B>1024523) B-=1024523;//取膜
}
int cur=0;
int main()
{
    n=read();m=read();
    scanf("%s",a+1);
    scanf("%s",b+1);
    f[0][0][0]=1;
    for (int i=0;i<=n;i++,cur^=1)
        for (int j=0;j<=m;j++)
            for (int k=0;k<=n;k++)
            {
                t=f[cur][j][k];
                if (i+j-k>m||i+j-k<0) continue;//越界退出
                if (a[i+1]==a[k+1]) add(t,f[cur^1][j][k+1]);//状态转移
                if (b[j+1]==b[i+j-k+1]) add(t,f[cur][j+1][k]);
                if (a[i+1]==b[i+j-k+1]) add(t,f[cur^1][j][k]);
                if (b[j+1]==a[k+1]) add(t,f[cur][j+1][k+1]);
                f[cur][j][k]=0;//清掉
            }
    printf("%d",f[cur][m][n]);
    return 0;
}