program chiclihescie;
var S,V,S1,B,A,X:real;n,m,i:integer;
begin
writeln ('vvedite A,B,N,M,X');
readln   ( A,B,N,M,X);
begin
for I:=m to n do
if ODD(N)
then v:=(A+X*i)/(B+X*i);
if odd(n)
then v:=-v;
S1:=A+B*V;
S:=S+S1;
writeln ('S=',s:4:2);
readln (s);
end;
end.