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 9.2.1) (judge verdict: Accepted)

#include <stdio.h>
#include <string.h>
int max(int a, int b){
    if(a<b)return b;
    else return a;
}
int min(int a, int b){
    if(a<b)return a;
    else return b;
}
int main(void){
    char s[500000+5];
    scanf("%s", s);
    int n=strlen(s);
    
    long int ans=0;
    // aの各項について、左に連続する < の個数と右の連続する > の個数の max が条件を満たす数列
    int i=0;
    while(i<n){
        int l=0, r=0;
        for(l=0 ; s[i]=='<'; i++, l++){}
        for(r=0 ; s[i]=='>'; i++, r++){}

        for(int j=1; j<min(r, l); j++)ans+=j;
        for(int j=1; j<=max(r, l); j++)ans+=j;
    }
    printf("%ld\n", ans);
}