program t1(input,output);
   var

   temp,data:array[1..52]of longint;
   i,j,s,g,ans:longint; ch:char;
   str:array[1..3000000]of integer;
     function deal(x:char):integer;
     begin
     if ord(x)<ord('a')
     then
     deal:=ord(x)-ord('A')+1
     else
     deal:=ord(x)-ord('a')+1+26;
     end;
   function check:boolean;
    var
    i:integer;
    begin
    check:=false;
    for i:= 1 to 52 do
    if temp[i]<>data[i] then exit;
    check:=true;
    end;
   begin
   fillchar(temp,sizeof(temp),0);
   fillchar(data,sizeof(data),0);
   fillchar(str,sizeof(str),0);
   ans:=0;
   assign(input,'writing.in');
   reset(input);
   readln(input,g,s);
   for i:= 1 to g do
   begin
   read(input,ch);
   inc(data[deal(ch)] ) ;
   end;
   readln(input);
   for i:= 1 to s do
    begin
    read(input,ch);
    str[i]:=deal(ch);
    end;
    close(input);
   for i:= 1 to g do
    begin
    inc(temp[str[i]]);
    end;
   if check then inc(ans);
   for i:=g+1 to s do
   begin
   dec(temp[str[i-g]]);
   inc(temp[str[i]]);
   if check then inc(ans);
   end;

   assign(output,'writing.out');
   rewrite(output);
   write(output,ans);
   close(output);

   end.