class Program { public static void main(String[] args) { Scanner Scan = new Scanner(System.in); System.out.print("A = "); int A = Scan.nextInt(); System.out.print("B = "); int B = Scan.nextInt(); System.out.print("N = "); int N = Scan.nextInt(); double R = 0; switch(N) { case 1: R = A+B; break; case 2: R = A-B; break; case 3: R = A*B; break; case 4: R = A/B; break; } System.out.println(R); } }
var t:real;
begin
t:=ArcTan(Sqrt(1-x*x)/x);
if x<0 then ArcCos:=t+Pi
else ArcCos:=t
end;
var
a,b,c,p,p2,s,alpha,beta,gamma,h:real;
begin
Read(a,b,p);
c:=p-a-b;
p2:=p/2;
s:=sqrt(p2*(p2-a)*(p2-b)*(p2-c));
alpha:=ArcCos((b*b+c*c-a*a)/(2*b*c));
beta:=ArcCos((a*a+c*c-b*b)/(2*a*c));
h:=a*Sin(beta);
alpha:=alpha*180/Pi;
beta:=beta*180/Pi;
gamma:=180-alpha-beta;
Writeln('c=',c);
Writeln('alpha=',alpha:0:2,', beta=',beta:0:2,', gamma=',gamma:0:2);
Writeln('S=',s,', h=',h)
end.