Int main(void)

{

float a, b, c, d;

cout<<"a=";

cin>>a;

cout<<"b=";

cin>>b;

cout<<"c=";

cin>>c;

cout<<"d=";

cin>>d;

if ((a>0) && (b>0) && (c>0) && (d>0) && (((a==b) &&

(c==d)) || ((a==d) && (c==b)) || ((a==c) && (b==d))))

cout<<"MOZHNO sostavit parallelogramm"; else

cout<<"NELZYA sostavit parallelogramm";

_getch();

return 0;

}