#include <stdio.h>
#include <string.h>
#include <math.h>

main() {
    double dist;
    int x1 = 10, x2 = 20, y1 = 30, y2= 50;
    
    dist = sqrt(pow(x2 - x1, 2) + pow(y2 - y1, 2));
            printf("%.2lf", dist);
    return 0;
}