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
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#include <list>
#include <ctime>
#include <sstream>
#include <queue>
#include <stack>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
using namespace std;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef long long ll;
typedef short int sint;
#define FOR(x, b, e) for(int x=(b); x<=(e); ++x)
#define FORD(x, b, e) for(int x=((int)(b))-1; x>=(e); --x)
#define REP(x, n) for(int x=0; x<(n); ++x)
#define ALL(c) c.begin(),c.end()
#define SIZE(x) ((int)((x).size()))
#define PB push_back
#define ST first
#define ND second
#define mp(x,y) make_pair(x,y)
#define DEBUG 1
#define debug(x) {if (DEBUG)cerr <<#x <<" = " <<x <<endl; }
#define debugv(x) {if (DEBUG) {cerr <<#x <<" = "; FOREACH(it, (x)) cerr <<*it <<", "; cout <<endl; }}
#define REMAX(a,b) (a)=max((a),(b));
#define REMIN(a,b) (a)=min((a),(b));
#define wez(n) int (n); scanf("%d",&(n));
#define wez2(n,m) int (n),(m); scanf("%d %d",&(n),&(m));

const int N = 202010;
int tab[N];
int n;

string toString(int x) {
	ostringstream s;
	s << x;
	return s.str();
}

struct Num {
	string pref; // first 10 chars
	int nastLen; // length after pref, if pref has 10 chars
	int suffix;  // the ending numbers of the suffix, helpful to check if we can do suffix+1 != 10^suffLen

	Num(string pref_, int suffLen_ = 0, int suffix_ = 0): pref(pref_), nastLen(suffLen_), suffix(suffix_) {
	}

	int size() const {
		return nastLen + pref.size();
	}
};

bool canIncreaseSuffix(Num a) {
	return (a.nastLen > 6 || pow(10, a.nastLen) > a.suffix + 1);
}

bool canIncreaseString(string x) {
	REP(i, x.size()) {
		if (x[i] != '9') {
			return true;
		}
	}
	return false;
}

Num addZeros(string nextStringNum, int dod) {
	while (dod > 0 && nextStringNum.size() < 10) {
		nextStringNum += '0';
		--dod;
	}
	return Num(nextStringNum, dod, 0);
}

pair<int, Num> getNext(int num, Num cur) {
	string nextStringNum = toString(num);
	if (nextStringNum.size() > cur.size()) {
		return mp(0, Num(nextStringNum));
	} else if (nextStringNum.size() == cur.size()) {
		// nastLen = 0, by def as nextStringNum.size < 10, or 10 if num = 10^9
		if (nextStringNum > cur.pref) {
			return mp(0, Num(nextStringNum));
		} else {
			return mp(1, addZeros(nextStringNum, 1));
		}
	} else {
		int nextNumLen = nextStringNum.size();
		int curLen = cur.size();
		int dod = curLen - nextNumLen;
		string curPref = cur.pref.substr(0, nextNumLen);
		if (nextStringNum > curPref) {
			// only add zeros to make the sizes same
			return mp(dod, addZeros(nextStringNum, dod));
		} else {
			if (curPref == nextStringNum) {
				// same prefix, check if we can 
				if (canIncreaseSuffix(cur)) {
					return mp(dod, Num(cur.pref, cur.nastLen, cur.suffix + 1));
				} else {
					// can increase the rest of the suffix of the prefix of the existing last number
					string curPrefSuffix = cur.pref.substr(nextNumLen, cur.pref.size() - nextNumLen);
					if (canIncreaseString(curPrefSuffix)) {
						int lastSuf = stoi(curPrefSuffix) + 1 + pow(10, curPrefSuffix.size());
						string lastSufStringPlus1e9 = toString(lastSuf);
						return mp(dod, Num(nextStringNum + lastSufStringPlus1e9.substr(1, string::npos), cur.nastLen, 0));
					} else {
						// just add 0
						return mp(dod + 1, addZeros(nextStringNum, dod + 1));
					}
				}
			} else {
				return mp(dod + 1, addZeros(nextStringNum, dod + 1));
			}
		}
	}
}

int main() {
	scanf("%d", &n);
	REP(i, n) {
		scanf("%d", &tab[i]);
	}
	Num cur(toString(tab[0]));
	ll result = 0;
	FOR(i, 1, n - 1) {
		pair<int, Num> res = getNext(tab[i], cur);
		result += res.ST;
		cur = res.ND;
		// cout << cur.pref << ' ' << cur.nastLen << ' ' << cur.suffix <<  endl;
	}
	cout << result << endl;
	return 0;
}