include <stdio.h>

int main(void)
{
int N = 0, sum = 0;
while(~scanf("%d", &N)){
sum = 0;
for(int i=1; i<=N; i++){
if(0 == i%7)sum++;
else if(7 == i%10)sum++;
else if(7 == i%100/10)sum++;
else if(7 == i%1000/100)sum++;
else if(7 == i%10000/1000)sum++;
}
printf("%d\n",sum);
}
return 0;
}