/* -*- coding: utf-8 -*-
 *
 * 2924.cc:  No.2924 <===Super Spaceship String===> - yukicoder
 */

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<utility>

using namespace std;

/* constant */

const int MAX_N = 500000;

/* typedef */

using pii = pair<int,int>;

/* global variables */

char s[MAX_N + 4];
pii ps[MAX_N], q[MAX_N];

/* subroutines */

/* main */

int main() {
  scanf("%s", s);
  int n = strlen(s);
  //printf(" n=%d\n", n);

  int m = 0;
  for (int i = 0; i < n;) {
    int j = i++;
    while (i < n && s[j] == '=' && s[i] == '=') i++;
    ps[m++] = {s[j], i - j};
  }
  //for (int i = 0; i < m; i++) printf(" %c,%d", ps[i].first, ps[i].second);
  //putchar('\n');
  
  int k = 0;
  for (int i = 0; i < m; i++) {
    auto [si, li] = ps[i];
    if (si == '<')
      q[k++] = {si, li};
    else if (si == '>') {
      if (k >= 2 && q[k - 1].first == '=' && q[k - 2].first == '<')
	k -= 2;
      else
	q[k++] = {si, li};
    }
    else {
      if (k >= 1 && q[k - 1].first == '=')
	q[k - 1].second += li;
      else
	q[k++] = {si, li};
    }
  }

  int sum = 0;
  for (int i = 0; i < k; i++) sum += q[i].second;
  
  printf("%d\n", sum);

  return 0;
}