program chiclihescie;
var S,V,S1,B,A,X:real;n,m,i:integer;
Function minusOnePower(i: Integer): Integer;
  Begin
    minusOnePower := (1 - 2*Byte(Odd(i)));
  End;
begin
writeln ('vvedite A,B,N,M,X');
readln   ( A,B,N,M,X);
S1:=A+B*V;
S:=S+S1;
begin
for I:=m to n do
V:= (Function minusOnePower(i: Integer): Integer)*[(A+X*i)/(B+X*i)];
end;
writeln ('s:=',S:6:4);
readln (s);
end.