사과

 

package backjoon;

import java.util.Scanner;

public class Apple {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int schoolCount = scanner.nextInt();

        int result = 0;
        for (int i = 0; i < schoolCount; i++) {
            int studentsCount = scanner.nextInt();
            int appleCount = scanner.nextInt();
            result += appleCount % studentsCount;

        }
        System.out.println(result);
    }
}