1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
#include <bits/stdc++.h>
#define dbg if(0)

using namespace std;
typedef long long ll;

ll get_length(ll a){
  if(a == 0)
    return 0;
  ll len = 1;
  while(a >= 10){
    a /= 10;
    len++;
  }
  return len;
}

ll get_digit(ll a, ll digit) {
  ll len = get_length(a);
  assert(digit <= len);
  for(ll i = 0; i < len-digit; ++i)
    a /= 10;
  
  return a%10;
}
ll get_digit_for_compound(ll a, ll current_zeros, ll added, ll i){
  ll len_a = get_length(a);
  //cerr << "a" << a << "len_a: " << len_a << " i: " << i << endl;
  if(len_a >= i)
    return get_digit(a, i);
  
  ll disposable_zeros = current_zeros - get_length(added);
  if(i > len_a && i <= len_a + disposable_zeros)
    return 0;
  
 // cerr << "xD hiho" << endl;
  return get_digit(added, i-len_a-disposable_zeros);
}

void prll_compound(ll a, ll current_zeros, ll added){
  ll pure_zeros = current_zeros - get_length(added);
  cout << "current zeros: " << current_zeros << " added: " << added << " purezeros:" << pure_zeros << " ";
  cout << a;
  for(ll i = 0; i < pure_zeros; ++i)
    cout << 0;
  
  if(added> 0)
  cout << added; 
  cout << " og: " << a << endl;
}

ll can_add_padded(ll a, ll current_zeros, ll added, ll current_a) {
  if(current_zeros > 8){ // sprobuj dodac
    //cerr << "here!" << endl;
    ll new_added = added+1;
    //ll disposable = get_length(a) + current_zeros - get_length(current_a);
    //cerr << "disposable: " << disposable << " get len: " << get_length(new_added) << endl;
    //cerr << "new_added: " << new_added << endl;
    if(get_length(new_added) > current_zeros){
    //  cerr << "Sad" << endl;
    return -1;
    }
    else return new_added;


  } else { // sklej i dodaj
  
    ll pow = 1ll;
    for(ll i = 0; i < current_zeros; ++i){
      pow *= 10;
    }
    ll new_a = a*pow + added + 1;
  //  cerr << "new_a: " << new_a << endl;

    for(ll i = 1; i <= get_length(current_a); ++i){
      if(get_digit(current_a, i) != get_digit(new_a, i)) return -1;
    }
    
    ll total_len = get_length(a) + current_zeros;
    ll disposable = total_len - get_length(current_a);
    pow = 1;
    for(ll i = 0; i < disposable; ++i){
      pow *= 10;
    }
    new_a = new_a%pow;

    return new_a;
  }
  return -1;
}


int main() {
  ios_base::sync_with_stdio(false);
  ll N;
  cin >> N;
  vector<ll> a(N);
  
  for(ll i = 0; i < N; ++i){
    cin >> a[i];
  }
  ll zeros_counter = 0;
  ll current_zeros = 0;
  ll added = 0;
  ll current_digit = get_digit(a[0], 1);
  //cerr << "looking at: " << a[0] << " digit is: " << current_digit << endl;
  ll total_len;
  ll zeros_to_add;
  //cout << a[0] << " og: " << a[0] << endl;
  for(ll i = 1; i < N; ++i) {
    ll next_digit = get_digit(a[i], 1);
    total_len = get_length(a[i-1]) + current_zeros;
    ll new_added = 0;
    zeros_to_add = 0;
    dbg cerr << "previous is: " << a[i-1] << " digit is: " << current_digit << " zeros: " << current_zeros << " add: " << added << endl;
    dbg cerr << "looking at: " << a[i] << " digit is: " << next_digit << endl;


    if(next_digit < current_digit) {
      zeros_to_add = total_len - get_length(a[i]) + 1;
    } else if(next_digit > current_digit) {
      zeros_to_add = total_len - get_length(a[i]);
    } else if(next_digit == current_digit) {
      // first check if a[i] is bigger than previous
      ll add_more = -1;
      ll next_len = get_length(a[i]);
      if(next_len <= total_len) {
          //prll_compound(a[i-1], current_zeros, added);
          //cerr << "a[i] " << a[i] << endl;

        for(ll j = 1; j <= next_len; ++j) {
          ll next_d = get_digit(a[i], j);
          ll current_d = get_digit_for_compound(a[i-1], current_zeros, added, j);
          //cerr << "next_d: " << next_d << " current_d: " << current_d << endl;
          if(next_d > current_d) {
            add_more = 0;
            dbg cerr << "addmore=0" << endl;
            break;
          } else if(next_d < current_d) {
            add_more = 1;
            dbg cerr << "addmore=1" << endl;
            break;
          }
        }
        
        if(add_more == -1) {
          ll res = can_add_padded(a[i-1], current_zeros, added, a[i]);
          if(res != -1){
            //cerr << "CAN ADD!, res: " << res << endl;
            add_more = 0; 
            new_added = res; 
          }else{
        //    cerr << "hiho" << endl;
            add_more = 1;
            new_added = 0;
          }
          
        if(current_zeros > 8 && get_length(a[i-1]) > next_len && !add_more) {
          zeros_counter += (get_length(a[i-1]) - next_len);
          a[i] = a[i-1];
          
        }

        }

        assert(add_more != -1);
        total_len = (get_length(a[i-1]) + current_zeros);
        zeros_to_add = total_len - get_length(a[i]) + add_more;
        
        

        }
      }
      if(zeros_to_add >= 0){
        current_zeros = zeros_to_add;
        zeros_counter += current_zeros;
        added = new_added;
      }else {
        current_zeros = 0;
        added = 0;
      }
      //cerr << "zeros_counter: " << zeros_counter << " ";
      //prll_compound(a[i], current_zeros, added);
      current_digit = next_digit;
  }
  
  cout << zeros_counter << endl;
  return 0;
}