dalex

const
    eps: double = 1e-9;

type
    bottle = record
        i, c1, c2: longint;
        v: double;
    end;

    cup = record
        i: longint;
        b: array[1..50] of double;
        v: double;
    end;

var
    k, i, j, n, m: longint;
    w, w0: double;
    b: array[1..50] of bottle;
    c: array[1..50] of cup;
    f: boolean;

begin
    read(n, w, m);
    if 2 * n < m then begin
        writeln('NO');
        halt;
    end;
    w0 := n * w / m;
    for i := 1 to n do begin
        b[i].i := i;
        b[i].c1 := 0;
        b[i].c2 := 0;
        b[i].v := w;
    end;
    for i := 1 to m do begin
        c[i].i := i;
        c[i].v := 0;
        for j := 1 to n do c[i].b[j] := 0;
    end;
    for k := 1 to 2 * n do begin
        i := (k + 1) div 2;
        if abs(b[i].v) < eps then continue;
        for j := 1 to m do begin
            if abs(c[j].v - w0) < eps then continue;
            if (b[i].c1 = j) or (b[i].c2 = j) then continue;
            if (b[i].c1 <> 0) and (b[i].c2 <> 0) then continue;
            if b[i].c1 = 0 then
                b[i].c1 := j
            else
                b[i].c2 := j;
            if b[i].v > w0 - c[j].v + eps then begin
                b[i].v := b[i].v - (w0 - c[j].v);
                c[j].b[b[i].i] := w0 - c[j].v;
                c[j].v := w0;
            end else begin
                c[j].v := c[j].v + b[i].v;
                c[j].b[b[i].i] := b[i].v;
                b[i].v := 0;
            end;
            break;
        end;
    end;
    for i := 1 to m do begin
        if abs(c[i].v - w0) > eps then begin
            writeln('NO');
            halt;
        end;
    end;
    writeln('YES');
    for i := 1 to m do begin
        f := true;
        for j := 1 to n do begin
            if c[i].b[j] > eps then begin
                if f then f := false else write(' ');
                write(j, ' ', c[i].b[j]:0:12);
            end;
        end;
        writeln;
    end;
end.