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++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <iostream> 
#include <string>
using namespace std;
int main(){
    int x=0, y=0, score=0, n=0;
    string a;
    cin >> a;
    n=a.size();
    if(a[0]=='<'){
        score+=x;
        x++;
    }
    else{
        y++;
    }
    for(int i=1; i<a.size(); i++){
        if(a[i-1]=='<'){
            if(a[i]=='<'){
                score+=x;
                x++;
            }
            else{
                y++;
            }
        } 
        if(a[i-1]=='>'){
            if(a[i]=='>'){
                y++;
            }
            else{
                score+=(y+1)*y/2;
                if(x>y){
                    score+=x-y;
                }
                y=0;
                x=1;
            }
        }   
    }
    if(a[n-1]=='>'&&a[n-2]=='>'){
        score+=(y+1)*y/2;
    }
    else if(a[n-1]=='<'&&a[n-2]=='>'){
        score++;
    }
    else{
        score+=x;
    }
    cout << score << endl;
    return 0;
}