C :

#include<stdio.h>
int main(void)
{
	int x;
	scanf("%d",&x);
	if(x<1)
		printf("%d\n",x);
	else
	{
	if(x>=10)
		printf("%d\n",3*x-11);
	else
		printf("%d\n",2*x-1);
	}
	return 0;
}

C++ :

#include<bits/stdc++.h>
using namespace std;
int x,y;
int main()
{
	cin>>x;
	if(x<1)y=x;
	else if(1<=x&&x<10)y=2*x-1;
	else if(x>=10)y=3*x-11;
	cout<<y;
   	return 0;
}