#include <bits/stdc++.h>
using namespace std;
void rset();
void init_test();
void solve();
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed;
  cout.precision(20);
  init_test();
  return 0;
}
template <typename T>
void chmin(T& a, T b) {
  if (a > b) a = b;
}
template <typename T>
void chmax(T& a, T b) {
  if (a < b) a = b;
}
template <typename T>
void MACRO_rdv2_Init(int n, T& t) {
  t.resize(n);
}
template <typename First, typename... Rest>
void MACRO_rdv2_Init(int n, First& first, Rest&... rest) {
  first.resize(n);
  MACRO_rdv2_Init(n, rest...);
}
template <typename T>
void MACRO_rdv2_Scan(int p, T& t) {
  std::cin >> t[p];
}
template <typename First, typename... Rest>
void MACRO_rdv2_Scan(int p, First& first, Rest&... rest) {
  std::cin >> first[p];
  MACRO_rdv2_Scan(p, rest...);
}
template <typename T>
void wrv(const vector<T>& v) {
  for (int(__ii) = (0); (__ii) < (((int)v.size())); ++(__ii)) {
    if (__ii) cout << ' ';
    cout << v[__ii];
  }
  cout << '\n';
}
template <typename T>
void wrm(const vector<vector<T>>& v) {
  for (int(__ii) = (0); (__ii) < (((int)v.size())); ++(__ii)) {
    for (int(__jj) = (0); (__jj) < (v[__ii].size()); ++(__jj)) {
      if (__jj) cout << ' ';
      cout << v[__ii][__jj];
    }
    cout << '\n';
  }
}
template <typename T>
void sc(T& x) {
  cin >> x;
}
template <typename Head, typename... Tail>
void sc(Head& head, Tail&... tail) {
  cin >> head;
  sc(tail...);
}
template <typename T>
void wr(const T& x) {
  cout << x << '\n';
}
template <typename Head, typename... Tail>
void wr(const Head& head, const Tail&... tail) {
  cout << head << ' ';
  wr(tail...);
}
template <typename T>
void wrf(const T& x) {
  cout << x << endl;
}
template <typename Head, typename... Tail>
void wrf(const Head& head, const Tail&... tail) {
  cout << head << ' ';
  wrf(tail...);
}
template <typename T>
void debug_out(const T& x) {
  cerr << x << '\n';
}
template <typename Head, typename... Tail>
void debug_out(const Head& head, const Tail&... tail) {
  cerr << head << ' ';
  debug_out(tail...);
}
template <typename... T>
void err(const T&... cod) {
  wr(cod...);
  exit(0);
}
bool can(int n, int len, vector<pair<int, int>>& v) {
  int cur = 0;
  for (int(i) = (0); (i) < (((int)v.size())); ++(i))
    if (v[i].first > len) return false;
  for (int(i) = (0); (i) < (((int)v.size())); ++(i)) {
    if (v[i].second == 0) {
      --n;
      cur = v[i].first;
    } else {
      if (cur + v[i].first <= len)
        cur += v[i].first;
      else
        --n, cur = v[i].first;
    }
  }
  return n > 0;
}
void solve() {
  int n;
  sc(n);
  cin.ignore();
  string a;
  getline(cin, a);
  vector<pair<int, int>> v;
  int s = 0;
  char lst = ' ';
  for (int(i) = (0); (i) < (((int)a.size())); ++(i)) {
    if (a[i] == '-' || a[i] == ' ' || i == ((int)a.size()) - 1) {
      if (lst == ' ')
        v.emplace_back(s + 1, 1);
      else
        v.emplace_back(s + 1, 1);
      s = 0;
      lst = a[i];
    } else {
      ++s;
    }
  }
  int low = 0, high = ((int)a.size()) + 1;
  while (low + 1 < high) {
    int mid = (low + high) / 2;
    if (can(n, mid, v))
      high = mid;
    else
      low = mid;
  }
  wr(high);
}
void init_test() {
  int qq = 1;
  while (qq--) solve();
}
