#include <iostream>
using namespace std;
bool IsSeven(int num)
{
while(num) {
if (num % 10 == 7) {
return true;
}
num /= 10;
}
return false;
}
/*
思路:若num能够整除7,则计数器累加; 若num中含有7的数字,则计数器累加。
*/
int CaculateSevenRelation(int num)
{
int countSum = 0;
int temp = 0;
for(int i = 1; i <= num; i++) {
if(i % 7 == 0) {
countSum++;
continue;
} else {
if(IsSeven(i)) {
countSum++;
}
}
}
return countSum;
}
int main()
{
int num;
while(cin>>num) {
cout<<CaculateSevenRelation(num)<<endl;
}
}