C :

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

C++ :

#include<iostream>
using namespace std;
int main()
{
  int x,y;
  cin>>x;
  if(x<1)
    y=x;
  else if(x<10)
    y=2*x-1;
    else
    y=3*x-11;
    cout<<y<<endl;
  return 0;
}