题解 | #判断字母#
判断字母
http://www.nowcoder.com/practice/44d2d63103664913bc243d3836b4f341
```var str = readline();
var num = str.charCodeAt();
if (num >= 'A'.charCodeAt() && num <= 'Z'.charCodeAt() || num >= 'a'.charCodeAt() && num <= 'z'.charCodeAt()) {
console.log('YES');
} else {
console.log('NO');
}
