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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
#define int long long
using namespace std;
signed main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	string s;
	cin>>s;
	s.push_back('#');
	int n=s.size();
	int ans=0, cur=0;
	vector<int>v;
	if(s[0]=='>') v.push_back(0);
	for(int i=0;i<n;i++){
		if(i==0) cur++;
		else if(s[i]!=s[i-1]){
			v.push_back(cur);
			ans+=cur*(cur-1)/2;
			cur=1;
		}
		else cur++;
	}
	if(s[n-2]=='<') v.push_back(0);
	//if(s[0]=='<'){
		for(int i=0;i<v.size()-1;i+=2){
			ans+=max(v[i], v[i+1]);
		}
	//}
	cout<<ans;
}