program E;
var
        f:text;
        mas1,mas2:array[1..20,1..100000] of char;
        i,j,n,m,kil:longint;
function InStr(i:integer):boolean;
var
        j:longint;
        res:boolean;
begin
        j:=1;
        res:=true;
        while (res)and(j<=m) do begin
                if mas1[i,j]<>mas2[i,j] then res:=false;
                j:=j+1;
        end;
        InStr:=res;
end;
{___________________________________}
procedure MyShr;
var
        i,j:longint;
begin
        for j:=m downto 1 do mas2[1,j+1]:=mas2[1,j];
        for j:=m downto 1 do mas2[n-1,j+1]:=mas2[n-1,j];
        mas2[1,1]:=mas2[1,m+1];
        mas2[n-1,1]:=mas2[n-1,m+1];
        kil:=kil+1;
end;
{_____________________________________}
function Mas1Mas2:boolean;
begin
        if (InStr(1))and(InStr(n-1)) then Mas1Mas2:=true else Mas1Mas2:=false;
end;
{_____________________________________}
begin
        assign(f,'repair.in');
        reset(f);
        readln(f,n,m);
        for i:=1 to n do begin
                for j:=1 to m do read(f,mas1[i,j]);
                readln(f);
        end;
        for i:=1 to n do begin
                for j:=1 to m do read(f,mas2[i,j]);
                readln(f);
        end;
        close(f);
        assign(f,'repair.out');
        kil:=0;
        while not Mas1Mas2 do MyShr;
        rewrite(f);
        write(f,kil);
        close(f);
end.