#include<iostream>
#include<algorithm>
#include<queue>
#include<deque>
#include<vector>
using namespace std;
#define ll long long
const int N = 1e6+10;
string s;

void solve()
{
	cin >> s;
	int len = s.length();
	int cnt = 0;
	if (len ==1&&(s[0]-'0'<6))
	{
		cout << 1;
	}
	else if (len == 1 && (s[0] - '0' >= 6))
	{
		cout << 2;
	}
	if (len % 6 == 0) {
		int  m = len / 5;
		cout << len + m + 1;
	
	}
	else if (len % 5 == 0)
	{
		int  m = len / 5;
		cout << len + m + 1;
	
	}
	else if (len % 5 != 0&&len%6!=0) {
		int  m = len / 5;
		cout << len + m+1;
		
	}

	
}
struct node {
	string s;
	double score;
	int get=0;
}arr[6];
int cmp(node s1, node s2)
{
	return s1.score > s2.score;
}
int main()
{
	
		solve();
}