Div 3
Problem Description
There is sequence 1, 12, 123, 1234, …, 12345678910, … . Given first N elements of that sequence. You must determine amount of numbers in it that are divisible by 3.
Input
Input contains N (1<=N<=2^31 - 1).
Output
Write answer to the output.
Sample Input
4
Sample Output
2
Solution
代码语言：javascript复制#include <bits/stdc .h>
int main() {
std::ios::sync_with_stdio(false);
int n{};
std::cin >> n;
std::cout << n / 3 * 2 (n % 3 > 1) << std::endl;
return 0;
}
