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<stdio.h>

int calc(int start, int end, char *S){
    int a;
}

int main(void){
    char S[5*100000+3];
    long long cnt_p = 0, cnt_m = 0;
    long long ans = 0;

    scanf("%s", S);

    int i = 0;
    for(i = 0; S[i] != '\0'; i++){
        if(S[i] == '>'){
            cnt_m++;
        }else{
            cnt_p++;
        }
        if((S[i]=='>' && S[i+1] == '<') || S[i+1] == '\0'){
            if(cnt_p >= cnt_m){
                ans += cnt_p*(cnt_p+1)/2 + cnt_m*(cnt_m-1)/2;
            }else{
                ans += cnt_p*(cnt_p-1)/2 + cnt_m*(cnt_m+1)/2;
            }
            cnt_p = 0;
            cnt_m = 0;
        }
        

    }

    printf("%lld", ans);
    return 0;
}