function Poly(str) {
    this.str = str;
    this.units = [];
    for (var i =0, len= str.length; i < len; ++i)
        if (this.units.indexOf(str[i].toLowerCase()) == -1)
            this.units.push(str[i].toLowerCase());
    this.units = this.units.sort();
}

Poly.checkReact = function(a, b) {
    return a.toLowerCase() == b.toLowerCase() && a !== b;
}

Poly.prototype.doReact = function() {
    for (var i =0, len= this.str.length -1; i < len; ++i)
        if (Poly.checkReact(this.str[i], this.str[i +1])) {
            this.str = this.str.substr(0, i) +this.str.substr(i +2);
            return true;
        }
    return false;
}

Poly.prototype.react = function() {
    var i = 0;
    while (this.doReact())
        ++i;
    return i;
}

function read(cb) {
    require("fs").readFile('./input', 'utf8', (err, data) => {
        var line = data.split("\n")[0];
        cb(line);
    });
}

function ex1() {
    read((polymereStr) => {
        var polymere = new Poly(polymereStr);
        polymere.react();
        console.log(polymere.str.length);
    });
}

function ex2() {
    read((polymereStr) => {
        var minPoly = null,
            minValue = 0,
            pos =0,
            poly = new Poly(polymereStr);
        poly.units.forEach((i) => {
            var p = new Poly(polymereStr.replace(new RegExp(i, "ig"), ""));
            p.react();
            if (minPoly ===null || minValue > p.str.length) {
                minPoly = i;
                minValue = p.str.length;
            }
            process.stdout.write('' +(++pos) +"/" +poly.units.length +"\r");
        });
        process.stdout.write("\n");
        console.log(minPoly, minValue);
    });
}

//ex1();
ex2();