var x1, y1, x2, y2, x3, y3, P: real;
function length(x1: real; y1: real; x2: real; y2: real): real;
begin
     length := sqrt(sqr(x1 - x2) + sqr(y1 - y2));
end;
begin
     read(x1, y1, x2, y2, x3, y3);
     P := length(x1, y1, x2, y2) + length(x3, y3, x2, y2) + length(x1, y1, x3, y3);
     writeln('Perimeter is ', P);
end.
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#include <cmath>
#include <iostream>

float length(float x1, float y1, float x2, float y2)
{
    return pow((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2), 0.5);
}
int main()
{
    float x1, y1, x2, y2, x3, y3, P;
    std::cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
    P = length(x1, y1, x2, y2) + length(x3, y3, x2, y2) + length(x1, y1, x3, y3);
    std::cout << "Perimeter is " << P;
}