var a=1;
function f(s, pos) {
    switch (s) {
    case "a":
        return (pos === "1");
    case "b":
break;
    case "c":
        switch (pos) {
case "f": return pos==="3";
case "f": return pos==="3";
default:return true;
}
    default:
        return false;
    }
}