const readline = require('readline'); const rl = readline.createInterface({ input:process.stdin, output:process.stdout }); rl.on('line',(line)=>{ let str = line; let result = line.split('').reduce((temp,data)=>{ temp[data]=temp[data]?temp[data] + 1: 1; return temp;//统计字母出现次数 },{}) let min = 21; for(let index in result){ min = Math.min(min,result[index]); } for(let index in result){ if(min === result[index]){ let reg = new RegExp(index, 'g') str = str.replace(reg, '') } } console.log(str) })