var
a : array[1..30000]of char;
ch:char;
n,i,c:longint;

procedure init;
begin
    readln(n);c:=0;
    for i:=1 to n do begin
    read(a[i]);
    end;
end;

procedure solve;
var q:boolean;
    j:longint;
begin
    i:=1;  q:=true;j:=0;
    while q and (j<1000000000) do begin
    q:=false;i:=1;inc(j);
    while i<=n do begin
        if (a[i]='>')and(a[i+1]='<') then begin
            a[i]:='<';a[i+1]:='>';inc(i);
            q:=true;inc(c);
        end;
        inc(i);
       end;
    end;
    if j<1000000000 then
    write(c) else write('NO');
end;

begin
    init;
    solve;
end.

Edited by author 23.02.2006 15:39