#include<stdio.h>
using namespace std;
void main()
{
for (int i=1, i<=5, i++)
{
for(int j=1, j<=i,j++)
{
printf("%c",64+j)
}
printf("
")
}
}
import math
x,y=input().split(),input().split()
x,y=[int(i) for i in x],[int(i) for i in y]
t,t1=abs(x[0]-y[0]),abs(x[1]-y[1])
print("%.2f" %math.sqrt(t*t+t1*t1))
np.linspace(0,1,11)