Problem:
Score : 300 points

Problem Statement

Given is a string S of length N-1.
Each character in S is < or >.

A sequence of N non-negative integers, a_1,a_2,\cdots,a_N, is said to be good when the following condition is satisfied for all i (1 \leq i \leq N-1):

If S_i= <: a_i<a_{i+1}

If S_i= >: a_i>a_{i+1}

Find the minimum possible sum of the elements of a good sequence of N non-negative integers.

Constraints

2 \leq N \leq 5 \times 10^5

S is a string of length N-1 consisting of < and >.

Input

Input is given from Standard Input in the following format:

S

Output

Find the minimum possible sum of the elements of a good sequence of N non-negative integers.

Sample Input 1

<>>

Sample Output 1

3

a=(0,2,1,0) is a good sequence whose sum is 3.
There is no good sequence whose sum is less than 3.

Sample Input 2

<>>><<><<<<<>>><

Sample Output 2

28

Solution in Pascal (FPC 2.6.2) (judge verdict: Accepted)

var
	S:String;
	N,id:Longint;
	ans,L,R:int64;
begin
	readln(S);
	N:=length(S);
	id:=1;
	ans:=0;
	while id<=N do begin
		L:=0;
		R:=0;
		while(id<=N)and(S[id]='<')do begin
			inc(id);
			inc(L);
		end;
		while(id<=N)and(S[id]='>')do begin
			inc(id);
			inc(R);
		end;
		inc(ans,L*(L+1)div 2+R*(R+1)div 2);
		if L<R then dec(ans,L)else dec(ans,R);
	end;
	writeln(ans);
end.