module swfsj7(input [1:0] SW,
    input KEY0,
    output [9:0] LEDR);

    zad3 ex(SW[1], KEY0, SW[0], LEDR[9]);
endmodule

module zad3(
    input w,clk,aclr,
    output reg z);

    reg [3:0] current, next;

    localparam [3:0]
            A = 4'b0000,
            B = 4'b0001,
            C = 4'b0010,
            D = 4'b0011,
            E = 4'b0100,
            F = 4'b0101,
            G = 4'b0110,
            H = 4'b0111,
            I = 4'b1000;

    always @(*)
    begin
        A:  if (!w) next = B;   else next = F;
    case (current)
        B:  if (!w) next = C;   else next = F;
        C:  if (!w) next = D;   else next = F;
        D:  if (!w) next = E;   else next = F;
        E:  if (!w) next = E;   else next = F;
        F:  if (!w) next = B;   else next = G;
        G:  if (!w) next = B;   else next = H;
        H:  if (!w) next = B;   else next = I;
        I:  if (!w) next = B;   else next = I;
        default:    next = 4'bxxxx;
    endcase
    z = (current == E) | (current == I);
    end

    always @(posedge clk,negedge aclr)
        if (~aclr)      current <= 0;
        else        current <= next;

endmodule