#include <stdio.h>

int avg(int a, int b, int c);

int main() {
    int a, b;
    scanf("%d %d", &a, &b);
    printf("%d\n", a+b);
    printf("%d\n", a-b);
    printf("%d\n", a*b);
    printf("%d\n", a/b);
    printf("%d\n", a%b);

    int num;
    scanf("%d", &num);
    if (num >= 1){
        printf("양수입니다.\n");
    }else if(num == 0){
        printf("0입니다.\n");
    }else{
        printf("음수입니다.\n");
    }

    for(int i=1;i<=10;i++){
        printf("%d\n", i);
    }
    for(int i=10;i>=1;i--){
        printf("%d\n", i);
    }

    int i = 0;
    while(1){
        if (i == 3){
            break;
        }
        printf("hello world!\n");
        i++;
    }

    int arr[10] = {2, 4, 6, 8, 10, 1, 3, 5, 7, 9};
    for(int i=0;i<10;i++){
        printf("%d\n", arr[i]);
    }

    printf("%d\n", avg(80, 70, 90));

    int score;
    scanf("%d", &score);
    if (score >= 90){ printf("A");}
    else if (score >= 80) { printf("B");}
    else if (score >= 70) {printf("C"); }
    else { printf("F");}
}

int avg(int a, int b, int c){
    return (a+b+c)/3;
}