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>
using namespace std;

#define rep(i,n) for(int i=0;i<n;++i)
#define rep1(i,n) for(int i=1;i<=n;++i)
#define all(x) x.begin(),x.end()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> P;
typedef pair<int,int> Pi;


int main(){
  string s;
  cin >> s;
  int n = s.size() + 1;		//文字列の長さ
  
  vector<ll> ans(n,0);
  
  rep(i, n-1){
    if(s.at(i) == '<'){
      ans.at(i+1) = ans.at(i) + 1;
    }
  }
  
  for(int i = n-2; i>=0; i--){
    if(s.at(i) == '>'){
      ans.at(i) = max(ans.at(i), ans.at(i+1) + 1);
    }
  }
  
  
  cout << accumulate(all(ans), 0LL) << endl;
}