Problem:
Score : 400 points

Problem Statement

Given are integers A, B, and N.

Find the maximum possible value of floor(Ax/B) - A × floor(x/B) for a non-negative integer x not greater than N.

Here floor(t) denotes the greatest integer not greater than the real number t.

Constraints

1 ≤ A ≤ 10^{6}

1 ≤ B ≤ 10^{12}

1 ≤ N ≤ 10^{12}

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B N

Output

Print the maximum possible value of floor(Ax/B) - A × floor(x/B) for a non-negative integer x not greater than N, as an integer.

Sample Input 1

5 7 4

Sample Output 1

2

When x=3, floor(Ax/B)-A×floor(x/B) = floor(15/7) - 5×floor(3/7) = 2. This is the maximum value possible.

Sample Input 2

11 10 9

Sample Output 2

9

Solution in Java (OpenJDK 11.0.6) (judge verdict: Runtime Error)

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;


	public class Main {
		
		public static int n;
		public static int m;
		public static int q;
		public static int max;
		
		public static int[] a ;
		public static int[] b ;
		public static int[] c ; 
		public static int[] d ;
		public static int[] f ;

		public static void main(String[] args) {

			Scanner sc = new Scanner(System.in);
			
			 n = sc.nextInt();
			 m = sc.nextInt();
			 q = sc.nextInt();
			 
			 a = new int[q];
			 b = new int[q];
			 c = new int[q];
			 d = new int[q];
			 f = new int[n];
			

			
			Map<Integer,Integer> map = new HashMap<Integer,Integer>();
			
			for(int i=0;i<q;i++) {
				a[i] = sc.nextInt();
				b[i] = sc.nextInt();
				c[i] = sc.nextInt();
				d[i] = sc.nextInt();
			}
			
			dfs(0,1);
			
			System.out.println(max);
			
		}
		
		private static void dfs(int inde, int num) {
			
			if(inde==n) {
				int count =0;
				
				for(int i=0;i<q;i++) {
					if(f[b[i]-1]-f[a[i]-1]==c[i]) {
						count+=d[i];
					}
				}
				
				max=Math.max(max, count);
				return;
			}
			
			
			for(int i=num;i<=m;i++) {
				f[inde] = i;
				dfs(inde+1,i);
				
			}
			
		}
		
	}