#include <iostream>
#include <math.h>
using namespace std;
bool ifSev(int num){//判断某一位有没有7,如果有,直接返回true
while(num > 0){
if(num % 10 == 7){
return true;
}
num /= 10;
}
return false;
}
int main(){
int n;
int count = 0;
while(cin >> n){
for(int i = 1; i <= n; i++){
if(i % 7 ==0){
count++;
continue;
}
if(ifSev(i)){
count++;
}
}
cout << count << endl;
}
}