#pragma GCC optimize("Ofast","unroll-loops")

#include <bits/stdc++.h>

#define rep(i, j, k) for (int i = (j); i <= (k); ++i)
#define per(i, j, k) for (int i = (j); i >= (k); --i)
#define SZ(v) int((v).size())
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second
using ll = long long;
using pii = std::pair<int, int>;
using pll = std::pair<ll, ll>;

template<class T>inline void chkmn(T &x, T y) { if (y < x) x = y; }
template<class T>inline void chkmx(T &x, T y) { if (y > x) x = y; }

using namespace std;

const int maxn = 450010;

string s, t;
int n, m, a[maxn], b[maxn], to[maxn][2];
vector<pii> val;

int main() {
  cin.tie(nullptr) -> ios::sync_with_stdio(false);
  s = "a"s, t = "b"s;
  while (SZ(t) < 450000) {
    string p = s + t;
    t = s, s = p;
  }
  t.resize(450000);
  cin >> s;
  if (t.find(s) != t.npos) return cout << SZ(s) << '\n', 0;
  n = SZ(s), m = SZ(t);
  rep (i, 1, n) a[i] = s[i - 1] - 'a';
  rep (i, 1, m) b[i] = t[i - 1] - 'a';
  to[m + 1][0] = to[m + 1][1] = m + 1;
  per (i, m, 1) {
    to[i][0] = to[i + 1][0], to[i][1] = to[i + 1][1];
    if (i != m) to[i][b[i + 1]] = i + 1;
  }
  rep (i, 1, m - n + 1) if (a[1] == b[i]) {
    int pos = i;
    rep (j, 1, min(n, 300)) pos = to[pos][a[j]];
    val.emplace_back(pos - i, i);
  }
  sort(ALL(val));
  int ans = 1e9;
  for (auto [len, i] : val) {
    if (clock() / CLOCKS_PER_SEC > 3.8) break;
    int pos = i;
    rep (j, 1, n) pos = to[pos][a[j]];
    chkmn(ans, pos - i + 1);
  }
  cout << ans << '\n';
}