function examPreparation(input) {

	let badGrades = Number(input.shift());

	let badGradesCounter = 0;
	let goodGradesCounter = 0;
	let gradesSum = 0;
	let lastProblem = "";
	let nameOfExercise;
	let grade = 0;

	while (badGradesCounter < badGrades) {
		nameOfExercise = input.shift();
		grade = Number(input.shift());

		if (nameOfExercise === 'Enough') {
			let totalCounter = badGradesCounter + goodGradesCounter;
			let averageScore = gradesSum / totalCounter;

			console.log(`Average score: ${averageScore.toFixed(2)}`);
			console.log(`Number of problems: ${totalCounter}`);
			console.log(`Last problem: ${lastProblem}`);
			break;
		}

		if (grade <= 4) {
			badGradesCounter++;
		} else {
			goodGradesCounter++;
		}

		lastProblem = nameOfExercise;
		gradesSum += grade;
	}

	if (badGradesCounter == badGrades) {
		console.log(`You need a break, ${badGradesCounter} poor grades.`);
	}
	
}

examPreparation(["3", "Money", "6", "Story", "4", "Spring Time", "5", "Bus", "6", "Enough"])