#include <iostream> #include <cmath> #include <iomanip> using namespace std; int main() { long double x[2],y[2]; cin>>x[0]>>y[0]; cin>>x[1]>>y[1]; cout << setprecision(18) <<(fabs(x[0]-x[1]) + fabs(y[0]-y[1]) - hypot(x[0]-x[1], y[0]-y[1])) <&l...