#include <bits/stdc++.h> using namespace std; double a1, b1, a2, b2; int main() { cin >>a1 >> b1 >> a2 >> b2; printf("%.4lf", sqrt((a1 - a2) * (a1 - a2) + (b1 - b2) * (b1 - b2))); }
对,我也是
对,我也是