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: Wrong Answer)

#include<bits/stdc++.h>
using namespace std;
using ll=long long;

int T(int n){
  return n*(n+1)/2;
}

int main(){
  int i,j,cnt=0;
  string s;
  cin>>s;
  if(s[0]=='>')s='<'+s[i];
  if(s[s.size()-1]=='<')s+='>';
  int n=s.size();
  int p[n];
  for(i=0;i<n;i++)p[i]=1;
  for(i=1;i<n;i++){
    if(s[i]==s[i-1]){
      p[cnt]++;
    }else cnt++;
  }
  int sum=0;
  for(i=0;i<=cnt/2;i++){
    sum+=T(max(p[2*i],p[2*i+1]))+T(min(p[2*i],p[2*i+1])-1);
  }
  cout<<sum;
}