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;
typedef long long ll; const ll MM = 1000000000;ll mod = MM + 7;
#define rep(i, n) for(ll i=0; i<n; i++)
#define Rep(i, j, n) for(int i=j; i<n; i++)
#define all(vec) vec.begin(), vec.end()
template<class T> inline bool chmin(T& a, T b) {if(a > b) {a = b; return true;} return false;}
template<class T> inline bool chmax(T& a, T b) {if(a < b) {a = b; return true;} return false;}
const ll INF = 1LL << 60;

int main() {
  string s; cin >> s;
  ll n = s.size();
  ll i=0, res=0;
  while(i<n) {
    int counts=0, countd=0;
    while(i<n && s[i] == '<') {
        counts++;
        i++;
    }
    while(i<n && s[i] == '>') {
        countd++;
        i++;
    }
    res += max(countd, counts);
    res += counts * (counts-1) / 2;
    res += countd * (countd-1) / 2;
  }
  cout << res << endl;
}