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;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
const long long MOD = 1e9+7, MAX = 1e18, larg = 1e5, INF = -1e9;
long long A,B,C,D,E,F,G,H,I,J,K,L,N,M,O,P,Q,R,S,T,U,V,W,X,Y,Z;
long long max_value = INF, max_index = -1;
long long min_value = MAX, min_index = -1;

typedef long long ll;
typedef pair<ll, ll> Pa;

/*2種類の連続した文字列を圧縮する*/
vector<int> strcompress(string S, int N){
    int count = 1;
    char c = S[0];
    vector<int> vec; 
	rep(i, N-1){
		if(c == S[i+1]){
			count++;
		}else{
			vec.push_back(count);
			count = 1;
			c = S[i+1];
		}
	}
	vec.push_back(count);
    return vec;
}

int main() {
    string s;
    cin >> s;
    vector<int> str = strcompress(s, s.size());
    int idx = 0;
    if(s[0] == '>') idx = 1;
    ll ans = 0;
    rep(i, str.size()-1){
        if(i%2 != idx) continue;
        if(str[i] < str[i+1]) str[i]--;
        else str[i+1]--;
    }
    rep(i, str.size()){
        ans += str[i]*(str[i]+1)/2;
    }
    cout << ans;
}