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: Accepted)

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define rep2(i,m,n) for(int (i)=(m);(i)<(n);(i)++)
const ll INF = 1LL<<60;
const ll MOD = 1e9+7;


int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    string s;cin>>s;
    int n = s.size()+1;
    vector<int> a(n,0),b(n,0);
    for(int i=1; i<n; i++){
        if(s[i-1]=='<')a[i]=a[i-1]+1;
        //else a[i]=0;

        if(s[n-i-1]=='>')b[n-i-1]=b[n-i]+1;
        
    }
    ll ans = 0;
    rep(i,n)ans+=max(a[i],b[i]);
    cout<<ans<<endl;
    //rep(i,n)cout<<max(a[i],b[i]);
    return 0;
}