498’.java

import java.util.*;
public class main{
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        while(input.hasNext()) {
        	int x = input.nextInt();
        	input.nextLine();
        	String str = input.nextLine();
        	String []str_arr = str.split(" ");
        	
        	int number[] = new int[str_arr.length * 2];
        	int j= 0;
        	int temp = 0;
        	temp = str_arr.length - 1;
        	
        	for(int i=0;i<(str_arr.length*2);i+=2) {
        		number[i] = Integer.parseInt(str_arr[j]);
        		number[i+1] = temp;
        		temp -= 1;
        		j++;
        	}
        	
			
        	if(number[1] == 1) {
        		System.out.println(number[0] * number[1]);
        	}
        	else {
        		for(int i=0;i<number.length;i+=2) {
        			number[i] = number[i+1] * number[i];
        			number[i+1] -= 1;
        		}
				
				int result = 0;
        		for(int i=0;i<number.length;i+=2) {
        			result += number[i] * Math.pow(x, number[i+1]);
           		}
           		
           		System.out.println(result);
       		}
        	
        }
    }
};