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#include <iostream>
#include <math.h>

using ull = unsigned long long int;
using namespace std;

typedef struct big_num {
  int log10 = 0;
  int size = 1;
  ull numbers[12000];
} big_num;

void print_big_num(big_num* a) {
  printf("%llu", a->numbers[0]);
  for (int i = 1; i < a->size; ++i) {
    printf("%018llu", a->numbers[i]);
  }
  printf("\n");
}

bool is_bigger_or_equal(big_num* a, big_num* b) {
  if (a->size > b->size)
    return true;
  if (a->size == b->size) {
    for (int i = 0; i < a->size-1; ++i) {
      if (a->numbers[i] > b->numbers[i])
        return true;
    }
    if (a->numbers[a->size - 1] >= b->numbers[b->size - 1])
      return true;
  }
  return false;
}

bool is_diff_major_bigger_than_current(big_num* a, ull current, int current_log10) {
  int segment_magnitude = (a->log10) % 18;
  int offset_magnitude = current_log10 - segment_magnitude + 1;

  ull tmp = a->numbers[0] % (ull)pow(10, segment_magnitude + 1);
  if (current_log10 < segment_magnitude) {
    tmp /= (ull)pow(10, segment_magnitude - current_log10);
  }
  if (offset_magnitude > 0 && a->size > 1) {
    tmp *= (ull)pow(10, offset_magnitude);
    tmp += a->numbers[1] / (ull)pow(10, offset_magnitude);
  }
    // divide a by 10^(magnitude) and compare to the current
  // int segment = magnitude / 18;
  // int offset = magnitude % 18;
  // ull offset_pow = pow(10, offset);
  // if (a->size < segment + 1) {
  //   return false;
  // }
  // if (a->size > segment + 2) {
  //   return true;
  // }
  // ull tmp = a->numbers[segment] / offset_pow;
  // // cout << a->numbers[segment] << endl;
  // // cout << "tmp: " << tmp << endl;
  // if (a->size >= segment + 2)
  //   tmp *= (a->numbers[segment - 1] % offset_pow);

  // cout << "segment : offset = " << segment_magnitude << " : " << offset_magnitude << endl;
  // cout << "current_log10: " << current_log10 << endl;
  // cout << "a.log10: " << a->log10 << endl;
  // cout << a->numbers[0] << endl;
  // // cout << "magnitude: " << magnitude << endl;
  // // cout << offset_pow << endl;
  // // print_big_num(a);
  // cout << "tmp: " << tmp << endl;
  // cout << "current: " << current << endl;
  // // }
  // if (tmp > current)
  //   cout << "TAK" << endl;
  // else
  //   cout << "NIE" << endl;
  return tmp > current;
}

void lift(big_num* a, int magnitude) {
  int blocks = magnitude / 18;
  int offset = magnitude % 18;
  ull offset_pow = pow(10, offset);
  a->size += blocks;
  if (offset > 0) {
    ull tmp = 0;
    ull tmp_prev = 0;
    // cout << "size: " << a->size << endl;
    for (int i = a->size - 1; i >= 0; --i) {
      tmp = 0;
      // tmp = a->numbers[i] / offset_pow;
      // a->numbers[i] = a->numbers[i] % offset_pow;
      for (int j = 0; j < offset; ++j) {
        a->numbers[i] *= 10;
        tmp *= 10;
        tmp += a->numbers[i] / (ull)1e18;
        a->numbers[i] = a->numbers[i] % (ull)1e18;
      }
      a->numbers[i] += tmp_prev;
      tmp_prev = tmp;
    }
    if (tmp > 0) {
      a->size++;
      for (int i = a->size - 1; i > 0; --i) {
        a->numbers[i] = a->numbers[i-1];
      }
      a->numbers[0] = tmp;
    }
  }
  a->log10 += magnitude;
}

bool check_mod_part_is_almost_full(big_num* a, int magnitude) {
  int blocks = magnitude / 18;
  int offset = magnitude % 18;
  ull offset_pow = pow(10, offset);
  for (int i = a->size - 1; i >= a->size - blocks; --i) {
    if (a->numbers[i] != (ull)1e18-1) {
      return false;
      // cout << "NIE1" << endl;
    }
  }
  if ((a->numbers[a->size - blocks - 1] % offset_pow) + 1 == offset_pow) {
    // cout << (a->numbers[a->size - blocks - 1] % offset_pow) << endl;
    // cout << "TAK" << endl;
    return true;
  }
  // cout << "NIE2" << endl;
  return false;
}

void increase_by_mod_part_plus_one(big_num* a, big_num* b, int magnitude) {
  // cout << "INC" << endl;
  // print_big_num(a);
  // print_big_num(b);
  // cout << "/INC" << endl;
  int blocks = magnitude / 18;
  int offset = magnitude % 18;
  ull offset_pow = pow(10, offset);
  for (int i = a->size - 1; i > a->size - blocks - 1; --i) {
    a->numbers[i] = b->numbers[i];
    // cout << "cos" << endl;
  }
  // cout << "b mod : " << b->numbers[a->size - blocks - 1] % offset_pow << endl;
  a->numbers[a->size - blocks - 1] += b->numbers[a->size - blocks - 1] % offset_pow;
  ull tmp = 0;
  a->numbers[a->size - 1] += 1;

  tmp = a->numbers[a->size - 1] / (ull)1e18;
  // cout << "tmp: " << tmp << endl;
  int i = a->size - 1;
  while(tmp) {
    a->numbers[i] = a->numbers[i] % (ull)1e18;
    --i;
    tmp = a->numbers[i] / (ull)1e18;
  }
}

int main() {
  int n;
  cin >> n;
  big_num *prev = new big_num;
  big_num *current = new big_num;
  ull counter = 0;
  cin >> prev->numbers[0];
  prev->size = 1;
  prev->log10 = floor(log10(prev->numbers[0]));
  for (int i = 1; i < n; ++i) {
    cin >> current->numbers[0];
    ull current_bak = current->numbers[0];
    current->size = 1;
    current->log10 = floor(log10(current->numbers[0]));
    int current_bak_log10 = current->log10;
    if (is_bigger_or_equal(prev, current)) {
      int log_diff = prev->log10 - current->log10;
      lift(current, log_diff);
      // print_big_num(current);
      // ull increaser = pow(10, log_diff);
      // current->numbers[0] *= increaser;
      // current->log10 += log_diff;
      counter += log_diff;
      if (is_bigger_or_equal(prev, current)) {
        // ull diff_major = (prev->numbers[0] / increaser) - current_bak;
        // ull diff_mod = prev->numbers[0] % increaser;
        if (is_diff_major_bigger_than_current(prev, current_bak, current_bak_log10) || check_mod_part_is_almost_full(prev, log_diff)) {
        // if (diff_major > 0 || ((diff_mod + 1) == increaser)) {
          lift(current, 1);
          // current->numbers[0] *= 10;
          // current->log10++;
          counter++;
        } else {
          increase_by_mod_part_plus_one(current, prev, log_diff);
          // current->numbers[0] += diff_mod + 1;
        }
      }
    }
    big_num* tmp = prev;
    prev = current;
    current = tmp;
    for (int i = 0; i < current->size; ++i)
      current->numbers[i] = 0;
    current->size = 1;
    // printf("prev: ");
    // print_big_num(prev);
    // cout << "prev: " << prev->numbers[0] << " : " << prev->numbers[1] << endl;
  }
  cout << counter << endl;
  return 0;
}