490a_team_olympiad.js

var n = parseInt(readline());
var s, skillsInput = readline().split(' ');
var skills = [];
var programmers = [];
var mathematicians = [];
var athletes = [];
var groups = [];

for (var i = 0; i < skillsInput.length; i++) {
    var skillCursor = parseInt(skillsInput[i]);
    switch (skillCursor) {
        case 1:
            programmers.push(i + 1);
            break;
        case 2:
            mathematicians.push(i + 1);
            break;
        case 3:
            athletes.push(i + 1);
            break;
        default:
            athletes.push(i + 1);
            break;
    }
}

for (var j = 0; j < programmers.length && j < mathematicians.length && j < athletes.length; j++) {
    groups.push({ programmer: programmers[j], mathematician: mathematicians[j], athlete: athletes[j] });
}

print(groups.length);

for (i = 0; i < groups.length; i++) {
    print(groups[i].programmer + " " + groups[i].mathematician + " " + groups[i].athlete);
}