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;

constexpr int N = 5e5 + 5;

char buf[N];

int solve() {
    auto sum_to = [](ll n) {
        return (n > 1 ? n * (n - 1) / 2 : 0);
    };
    scanf("%s", buf);
    int n = strlen(buf);
    ll res = 0;
    int o_count = 0, c_count = 0;
    for (int i = 0; i < n; ++i) {
        const char c = buf[i];
        if (c == '<') {
            if (c_count != 0) {
                res +=
                    sum_to(o_count) + sum_to(c_count) + max(o_count, c_count);
                o_count = 1;
                c_count = 0;
            } else {
                ++o_count;
            }
        } else {
            ++c_count;
        }
    }
    res += sum_to(o_count) + sum_to(c_count) + max(o_count, c_count);
    cout << res << endl;

    return 0;
}

int main() {
    freopen("input", "r", stdin);
    while (solve()) {
    }

    return 0;
}