program Project2;

{$APPTYPE CONSOLE}

var a,c:array[1..20,1..100000]of char;
    i,n,m,j,k:integer;  b,b1:char;  p:boolean;


begin
assign(Input,'repair.in');
reset(Input);
readln(n,m);
for i:=1 to n do                begin
  for j:=1 to m do read(c[i,j]);
  readln;
  end;

  for i:=1 to n do                begin
  for j:=1 to m do read(a[i,j]);
  readln;
  end;
close(Input);

assign(Output,'repair.out');
rewrite(Output);


 k:=0;
while not(p) do begin

 for j:=1 to n do begin
  b:=a[j,1];
  for i:=1 to m-1 do begin
   b1:=a[j,i+1];
   a[j,i+1]:=b;
   b:=b1;
   end;
   a[j,1]:=b;
  end;

          p:=true; i:=1;j:=1;
  while (p)and(i<=n) do begin
    while (p)and(j<=m) do begin
      if not(a[i,j]=c[i,j]) then p:=false;
      inc(j);
    end;
  inc(i);
end;
  inc(k);
  end;

  writeln(k);
close(Output);
end.