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#include <bits/stdc++.h>
using namespace std;

typedef long long LL;
typedef long double LD;
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<LL> VLL;
#define mp make_pair
#define pb push_back
#define st first
#define nd second

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	LL n, prv, cur;

	cin >> n;
	cin >> prv;

	LL res = 0;

	for (int i = 1; i < n; i++) {
		cin >> cur;
		LL m = 1;
		if (prv >= cur) {
			while (m*cur + m - 1 <= prv) {
				m *= 10;
				res++;
			}
			if (m*cur > prv) cur *= m;
			else cur = m*cur + (prv % m) + 1;
		}
		prv = cur;
	}

	cout << res;

	return 0;
}