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 5.4.1) (judge verdict: Accepted)

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#define int long long
int main()
{   char s[500005];
    scanf("%s",s);
    int l=strlen(s);
    long long a[l+2];
    for(int i=0;i<l+2;i++)a[i]=0;
    long long left=0,right=0,x=0;
    long long ans=0;
    for(int i=0;i<l;i++){
        if(s[i]=='<'){
            a[i]=left;
            left++;
        }else{
            a[i]=left;
            left=0;
        }
        if(i==l-1&&s[i]=='<'){
            a[l]=left;
        }
    }
    for(int i=l-1;i>=0;i--){
        if(s[i]=='>'){
            a[i+1]=right;
            right++;
            if(i==0){
                a[i]=right;
            }
        }else{
            a[i+1]=right>a[i+1]?right:a[i+1];
            right=0;
        }
        
        
    }
    //printf("%s\n",s);
    for(int i=0;i<l+1;i++){
        ans+=a[i];
        //printf("%d ",a[i]);
    }
    printf("%lld",ans);
    return 0;
}