#include<stdio.h>
int isIncludeNine(int n)
{
while(n)
{
if(n%10 == 9)
{
return 1;
break;
}
n /= 10;
}
return 0;
}
int main()
{
int count = 0;
for(int i = 1 ; i < 2020 ; i++)
{
if(isIncludeNine(i))
count++;
}
printf("%d\n",count);
return 0;
}

京公网安备 11010502036488号