AnnPol_23

Var
    B: Array [1..50] Of LongInt; R, U, D: Double;
    I: Integer;

Function F(A: LongInt): LongInt;
Begin
    If A Mod 3 = 0 Then
      F:= A
    Else If A Mod 3 = 1 Then
      F:= A * A
    Else
      F:= A Div 3;
End;

Function Fact(N: Integer): Double;
Var
    I: Integer;
    F: Double;
Begin
    If N = 1 Then
      Fact:= 1
    Else Begin
      F:= 1;
      For I:= 2 To N Do F:= F * I;
      Fact:= F;
    End;
End;

Begin
    For I:= 1 To 50 Do B[I]:= I;
    I:= 1;
    While I <= 49 Do Begin
      U:= U + F(B[I]) / Fact(I);
      D:= D + (F(B[I + 1])) / Fact(I + 1);
      I:= I + 2;
    End;
    R:= U / D;
    WriteLn('R=', R);
End.