#include <stdio.h>

int main() {
    printf("Hello world!\n");
    //실습5//
   /* int n;
    scanf("%d",&n);
    printf("입력받은 값= %d\n",n); */

    //실습6//
/* int a, b;
    scanf("%d", &a);
    scanf("%d", &b);
    printf("입력 받은 값= %d,%d\n",a,b);  */
 
    
    //실습7//
 /*   float a;
    scanf("%f",&a);
    printf("입력받은 값=%f\n",a);    */

    //실습8//
    double x,y;
    scanf("%lf%lf",&x,&y);
    printf("입력값=%.2lf, %.2lf\n",x,y);
    return 0;
}