while(line = readline()) {
    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 = Number.MAX_SAFE_INTEGER;
    for (let index in result) {    //计算最小出现次数
        min = Math.min(min, result[index]);
    }
    for (let index in result) {
        if (min == result[index]) {    // 正则replace掉
            let reg = new RegExp(index, 'g');
            str = str.replace(reg, '');
        }
    }
    print(str)
}