#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T bigmod(T p, T e, T M) {
  long long int ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % M;
    p = (p * p) % M;
  }
  return (T)ret;
}
template <class T>
inline T gcd(T a, T b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
template <class T>
inline T modinverse(T a, T M) {
  return bigmod(a, M - 2, M);
}
template <class T>
inline T bpow(T p, T e) {
  long long int ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p);
    p = (p * p);
  }
  return (T)ret;
}
int toInt(string s) {
  int sm;
  stringstream ss(s);
  ss >> sm;
  return sm;
}
int toLlint(string s) {
  long long int sm;
  stringstream ss(s);
  ss >> sm;
  return sm;
}
int ts, kk = 1;
int n, a[1000006];
bool bl[1000006];
char s[1000006];
int p[2][2][1000006];
int dp(bool st, bool c, int i) {
  if (i == n) {
    if (c && st) return -1;
    return 0;
  }
  int &pr = p[st][c][i];
  if (pr != -1) return pr;
  pr = 0;
  pr = max(pr, dp(st, 0, i + 1));
  if (bl[i] == 0) {
    if (c == 0) pr = max(dp((i == 0) || st, 1, i + 1) + 1, pr);
    if (a[i] > 1) pr = max(dp(st, 1, i + 1) + 1, pr);
  } else {
    if (c == 0) pr = max(dp((i == 0) || st, 1, i + 1) + 1, pr);
    if (a[i] > 1) pr = max(dp(st, 1, i + 1) + 1, pr);
  }
  return pr;
}
void prnt(bool st, bool c, int i) {
  if (i == n) {
    puts("");
    return;
  }
  int &pr = p[st][c][i];
  if (dp(st, 0, i + 1) == pr) {
    prnt(st, 0, i + 1);
    return;
  }
  if (bl[i] == 0) {
    if (c == 0 && dp((i == 0), 1, i + 1) + 1 == pr) {
      printf("%d 0 0\n", i);
      prnt((i == 0), 1, i + 1);
      return;
    }
    if (a[i] > 1 && pr == dp(st, 1, i + 1) + 1) {
      printf("%d 0 1\n", i);
      prnt(st, 1, i + 1);
      return;
    }
  } else {
    if (c == 0 && dp((i == 0), 1, i + 1) + 1 == pr) {
      printf("%d 1 0\n", i);
      prnt((i == 0), 1, i + 1);
      return;
    }
    if (a[i] > 1 && pr == dp(st, 1, i + 1) + 1) {
      printf("%d 1 1\n", i);
      prnt(st, 1, i + 1);
      return;
    }
  }
}
int main() {
  int t, i, j, k;
  memset(p, -1, sizeof(p));
  scanf(" %s", s);
  k = strlen(s);
  bl[0] = s[0] - '0';
  n = 1;
  for (i = 0; i < k; i++) {
    if ((bool)(s[i] - '0') == bl[n - 1])
      a[n - 1]++;
    else {
      bl[n] = (s[i] - '0');
      a[n++] = 1;
    }
  }
  if (n > 1 && bl[n - 1] == bl[0]) {
    a[0] += a[n - 1];
    n--;
  }
  k = dp(0, 0, 0);
  printf("%d\n", k);
  return 0;
}
