1 #include<iostream> 2 #include<cstring> 3 #include<cmath> 4 #include<cstdio> 5 using namespace std; 6 int main() 7 { 8     double x1,x2,y1,y2; 9     cin>>x1>>y1>>x2>>y2;10     printf("%.3lf",abs(x1-x2)+abs(y1-y2));11     return 0;12 }