// Problem: 1141_F2. Same Sum Blocks (Hard)
// Time complexity: quadratic
import java.io.*;
import java.util.*;
import java.util.stream.*;

public class ProblemF {
    private static boolean debug = false;

    private static int N;
    private static int[] A;

    private static void solveProblem(InputStream instr) throws Exception {
        InputReader sc = new InputReader(instr);
        int testCount = 1;
        if (debug) {
            testCount = sc.nextInt();
        }

        for (int t = 1; t <= testCount; t++) {
            printDebug("------ " + t + " ------");
            N = sc.nextInt();
            A = readInts(sc, N);
            Object result = solveTestCase();
            System.out.println(result);
        }
    }

    private static Object solveTestCase() {
        int sum[] = new int[N];
        sum[0] = A[0];
        for (int i = 1; i < N; i++) {
            sum[i] = sum[i - 1] + A[i];
        }
        Map<Integer, List<int[]>> map = new HashMap<>();
        for (int i = 0; i < N; i++) {
            for (int j = i; j < N; j++) {
                int groupSum = sum[j] - (i == 0 ? 0 : sum[i - 1]);
                map.putIfAbsent(groupSum, new ArrayList<>());
                map.get(groupSum).add(new int[]{i, j});
            }
        }
        int max = -1;
        List<int[]> maxAnswer = null;
        for (Map.Entry<Integer, List<int[]>> entry : map.entrySet()) {
            List<int[]> values = entry.getValue();
            if (values.size() <= max) {
                continue;
            }
            List<int[]> curr = findMax(values);
            if (curr.size() > max) {
                max = curr.size();
                maxAnswer = curr;

            }
        }
        List<String> answer = new ArrayList<>();
        for (int[] value : maxAnswer) {
            answer.add((value[0] + 1) + " " + (value[1] + 1));
        }
        return max + "\n" + joinValues(answer, "\n");
    }

    private static List<int[]> findMax(List<int[]> values) {
        values.sort(new Comparator<int[]>() {
            @Override
            public int compare(int[] o1, int[] o2) {
                return o1[1] - o2[1];
            }
        });
        List<int[]> answer = new ArrayList<>();
        int right = -1;
        for (int i = 0; i < values.size(); i++) {
            int[] value = values.get(i);
            if (value[0] > right) {
                answer.add(value);
                right = value[1];
            }
        }
        return answer;
    }

    private static int[] readInts(InputReader sc, int N) throws Exception {
        int[] arr = new int[N];
        for (int i = 0; i < N; i++) {
            arr[i] = sc.nextInt();
        }
        return arr;
    }

    private static String joinValues(List<? extends Object> list, String delim) {
        return list.stream().map(Object::toString).collect(Collectors.joining(delim));
    }

    private static String joinValues(int[] arr, String delim) {
        List<Object> list = new ArrayList<>();
        for (Object value : arr) {
            list.add(value);
        }
        return list.stream().map(Object::toString).collect(Collectors.joining(delim));
    }

    public static void printDebug(Object str) {
        if (debug) {
            System.out.println("DEBUG: " + str);
        }
    }

    private static final class InputReader {
        private final InputStream stream;
        private final byte[] buf = new byte[1024];
        private int curChar;
        private int Chars;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        private int read() throws Exception {
            if (curChar >= Chars) {
                curChar = 0;
                Chars = stream.read(buf);
                if (Chars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public final int nextInt() throws Exception {
            return (int)nextLong();
        }

        public final long nextLong() throws Exception {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
                if (c == -1)
                    throw new IOException();
            }
            boolean negative = false;
            if (c == '-') {
                negative = true;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += (c - '0');
                c = read();
            } while (!isSpaceChar(c));
            return negative ? (-res) : (res);
        }

        public final int[] nextIntBrray(int size) throws Exception {
            int[] arr = new int[size];
            for (int i = 0; i < size; i++)
                arr[i] = nextInt();
            return arr;
        }

        public final String next() throws Exception {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.append((char)c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public final String nextLine() throws Exception {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.append((char)c);
                c = read();
            } while (c != '\n' && c != -1);
            return res.toString();
        }

        private boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }
    }

    public static void main(String[] args) throws Exception {
        long currTime = System.currentTimeMillis();
        if (debug) {
            solveProblem(new FileInputStream(new File("input.in")));
            System.out.println("Time: " + (System.currentTimeMillis() - currTime));
        } else {
            solveProblem(System.in);
        }
    }

}