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)

// by newbiechd
#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <vector>

// DELETE the debugging information!
#define debug(x) std::cerr << #x << " = " << (x) << std::endl

const int N_MAX = 500003;
char s[N_MAX];
int pre[N_MAX], suf[N_MAX];

int main() {
  scanf("%s", s + 1);
  int n = strlen(s + 1) + 1;
  for (int i = 2; i <= n; ++i)
    pre[i] = s[i - 1] == '<' ? pre[i - 1] + 1 : 0;
  for (int i = n - 1; i > 0; --i)
    suf[i] = s[i] == '>' ? suf[i + 1] + 1 : 0;
  long long ans = 0;
  for (int i = 1; i <= n; ++i)
    ans += std::max(pre[i], suf[i]);
  printf("%lld\n", ans);
  return 0;
}