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: Wrong Answer)

#include <stdio.h>

int main(){
  char S[500000];
  scanf("%s",S);
  int i;
  for(i=0;S[i]!='\0';i++);
  int N=i+1;
  int A[N];
  int c1=0,c2=0;
  for(i=0;i<N;i++){
    if(S[i]=='<'){
      c1++;
    }else if(S[i]=='>'){
      c2++;
    }
    if((S[i]=='>'&&S[i+1]=='<')||S[i+1]=='\0'){
      for(int j=0;j<c1;j++){
        A[i-c1-c2+1+j]=j;
      }
      if(c1>=c2) A[i-c2+1]=c1;
      if(c1<c2) A[i-c2+1]=c2;
      for(int j=0;j<c2;j++){
        A[i+1-j]=j;
      }
    c1=c2=0;
    }
  }
  int sum=0;
  for(i=0;i<N;i++){
    sum+=A[i];
  }
  printf("%d",sum);
}