#include<stdio.h>
float zhu(float a,float b);
int main(void)
{
float x,y,z;
while(scanf("%f %f",&x,&y)==2)
{
z=zhu(x,y);
printf("%f",z);
}
return 0;
}
float zhu(float a,float b)
{
float c;
c=(a-b)/(a*b);
return c;
}
#include<stdio.h>
float zhu(float a,float b);
int main(void)
{
float x,y,z;
while(scanf("%f %f",&x,&y)==2)
{
z=zhu(x,y);
printf("%f",z);
}
return 0;
}
float zhu(float a,float b)
{
float c;
c=(a-b)/(a*b);
return c;
}