4 11.11

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Optional;

import static java.lang.System.out;

public final class Main {

    private static final int SIZE = 1000;

    public static final void main(final String[] args) throws IOException {
        try (final var reader = new BufferedReader(new InputStreamReader(System.in))) {
            final var nums = new double[SIZE];

            for (var i = 0; i < SIZE; i++)
                nums[i] = Double.parseDouble(reader.readLine().trim().replace(",", "."));

            var ind = 0;
            final var filter = new ArrayList<ArrayList<Double>>(1);

            while (ind < nums.length) {
                final var list = new ArrayList<Double>(1);
                list.add(nums[ind++]);

                while (ind < nums.length && Math.abs(nums[ind - 1] - nums[ind]) <= 2.0)
                    list.add(nums[ind++]);

                filter.add(list);
            }

            out.println(
                    filter.stream().map(list -> {
                        final var size = list.size();
                        final var dp = new double[size]; dp[0] = list.get(0);

                        for (var i = 1; i < size; i++)
                            dp[i] = Math.max(list.get(i), list.get(i) + dp[i - 1]);

                        return Arrays.stream(dp).max().getAsDouble();
                    }).max(Comparator.comparingDouble(Double::doubleValue)).get()
            );
        }
    }
}