#include <iostream>
#include <cmath>
using namespace std;
int main() {
double xa, xb, ya, yb, za, zb;
cin >> xa >> xb >> ya >> yb >> za >> zb;//вводим наши координаты
double AB = sqrt((xb-xa)*(xb-xa)+(yb-ya)*(yb-ya)+(zb-za)*(zb-za));
cout << AB;//выводим полученное расстояние
return 0;
}
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