// editor3
#include <stdio.h>
#include<math.h>

  int main() {
      int n;
      
      //read number of point pairs
      if(scanf("%d", &n)!=1) {
          printf("Invalid input");
          return 0;
      } 
      //Validate n 
      of (n< 0 || n>10) {
          printf("Invalid input");
          return 0;
      }
      
      for (int i=0; i<n; i++) {
          float x1,y1,x2,y2;
          
          //Read coordinates safely
          if (scanf("%f %f %f %f , &x1, &y1 ,&x2 ,&y2")!=4) {
              printf("Invalid input");
              return 0;
          }
          //calculate Euclidean distance
          float distance=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
          printf("%.2f,distance");
          
          if(i<n-1)
          printf("/n");
          }
          return 0;
  }