Problem:
Score : 400 points

Problem Statement

Snuke has one biscuit and zero Japanese yen (the currency) in his pocket.
He will perform the following operations exactly K times in total, in the order he likes:

Hit his pocket, which magically increases the number of biscuits by one.

Exchange A biscuits to 1 yen.

Exchange 1 yen to B biscuits.

Find the maximum possible number of biscuits in Snuke's pocket after K operations.

Constraints

1 \leq K,A,B \leq 10^9

K,A and B are integers.

Input

Input is given from Standard Input in the following format:

K A B

Output

Print the maximum possible number of biscuits in Snuke's pocket after K operations.

Sample Input 1

4 2 6

Sample Output 1

7

The number of biscuits in Snuke's pocket after K operations is maximized as follows:

Hit his pocket. Now he has 2 biscuits and 0 yen.

Exchange 2 biscuits to 1 yen. his pocket. Now he has 0 biscuits and 1 yen.

Hit his pocket. Now he has 1 biscuits and 1 yen.

Exchange 1 yen to 6 biscuits. his pocket. Now he has 7 biscuits and 0 yen.

Sample Input 2

7 3 4

Sample Output 2

8

Sample Input 3

314159265 35897932 384626433

Sample Output 3

48518828981938099

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int main(){
  int i,j=1;
  unsigned long long int a,b,k;
  unsigned long long int bis=1;
  scanf("%llu %llu %llu",&k,&a,&b);
  if(a>b){
    bis+=k;
  }
  else{
  while(k>0){
     if(k-a>=0){
       if(j==1){
         bis+=a-1;
         k-=a-1;
       j=0;
     }
       else{
         bis+=a;
           k-=a;
       }
     }
    else{
      bis+=k;
      k=0;
    }
    
  if(k>=2&&bis+2<b){
    bis-=a;
    bis+=b;
    k-=2;
  }
  else if(k==1){
      bis+=1;
      k=0;
    }
  else{
      if(k!=0){
        bis+=k;
        k=0;
      }
    }
  }
  }
  printf("%llu",bis);
}