Problem: You are given a function f written in some basic language. The function accepts an integer value, which is immediately written into some variable x. x is an integer variable and can be assigned values from 0 to 2^{32}-1. The function contains three types of commands:

  * for n — for loop; 
  * end — every command between "for n" and corresponding "end" is executed n times; 
  * add — adds 1 to x. 



After the execution of these commands, value of x is returned.

Every "for n" is matched with "end", thus the function is guaranteed to be valid. "for n" can be immediately followed by "end"."add" command can be outside of any for loops.

Notice that "add" commands might overflow the value of x! It means that the value of x becomes greater than 2^{32}-1 after some "add" command. 

Now you run f(0) and wonder if the resulting value of x is correct or some overflow made it incorrect.

If overflow happened then output "OVERFLOW!!!", otherwise print the resulting value of x.

Input

The first line contains a single integer l (1 ≤ l ≤ 10^5) — the number of lines in the function.

Each of the next l lines contains a single command of one of three types:

  * for n (1 ≤ n ≤ 100) — for loop; 
  * end — every command between "for n" and corresponding "end" is executed n times; 
  * add — adds 1 to x. 

Output

If overflow happened during execution of f(0), then output "OVERFLOW!!!", otherwise print the resulting value of x.

Examples

Input


9
add
for 43
end
for 10
for 15
add
end
add
end


Output


161


Input


2
for 62
end


Output


0


Input


11
for 100
for 100
for 100
for 100
for 100
add
end
end
end
end
end


Output


OVERFLOW!!!

Note

In the first example the first "add" is executed 1 time, the second "add" is executed 150 times and the last "add" is executed 10 times. Note that "for n" can be immediately followed by "end" and that "add" can be outside of any for loops.

In the second example there are no commands "add", thus the returning value is 0.

In the third example "add" command is executed too many times, which causes x to go over 2^{32}-1.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;

public class Main {
    static class FastScanner {
        private BufferedReader bufferedReader;
        private StringTokenizer stringTokenizer;
        public FastScanner(InputStream inputStream){
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        }
        public String next() {
            while (stringTokenizer == null || !stringTokenizer.hasMoreTokens()){
                try {
                    stringTokenizer = new StringTokenizer(bufferedReader.readLine());
                } catch (IOException ignored){}
            }
            return stringTokenizer.nextToken();
        }
        public int nextInt() {
            return Integer.parseInt(next());
        }
        public long nextLong() {
            return Long.parseLong(next());
        }
        public double nextDouble() {
            return Double.parseDouble(next());
        }
    }

    static class Node implements Comparable {
        Node left;
        Node right;
        private int value;

        Node(Node left, Node right, int value) {
            this.left = left;
            this.right = right;
            this.value = value;
        }

        @Override
        public int compareTo(Object o) {
            return Integer.compare(this.value, ((Node)o).value);
        }
    }

    private static int fib(int n, int m){
        if (n < 2) return n;
        int a = 0;
        int b = 1;
        for (int i=0;i<n-2;i++){
            int c = (a + b) % m;
            a = b;
            b = c;
        }
        return (a + b) % m;
    }

    static long gcd(long a, long b) {
        if (b == 0) return a;
        return gcd(b, a % b);
    }

    static long lcm(long a, long b) {
        return Math.abs(a * b) / gcd(a, b);
    }

    static class DSU {
        private int [] p;
        private int [] r;

        DSU(int n) {
            p = new int[n];
            r = new int[n];
            Arrays.fill(p, -1);
            Arrays.fill(r, 0);
        }

        int find(int x) {
            if (p[x] < 0) {
                return x;
            }
            return p[x] = find(p[x]);
        }

        void union(int a, int b) {
            a = find(a);
            b = find(b);
            if (a == b) return;
            if (r[a] < r[b]) {
                p[a] = b;
            }
            else {
                p[b] = a;
            }
            if (r[a] == r[b]) {
                r[a] ++;
            }
        }
    }

    private static boolean isPrime(long n) {
        for (int i = 2; i < n; i++) {
            if (n % i == 0) return false;
        }
        return true;
    }

    private static double med(Integer[]a) {
        Arrays.sort(a);
        if (a.length % 2 == 0) {
            int r = a.length / 2;
            int l = r-1;
            double s = a[l] + a[r];
            return s / 2.0;
        }
        int m = a.length / 2;
        return a[m];
    }

    static Map<Integer, ArrayList<Integer>>g;
    static Map<Integer, Integer> color;

    static void dfs(int v, int c) {
        color.put(v, c);
        for (int i = 0; i < g.get(v).size(); i++) {
            int u = g.get(v).get(i);
            if (!color.containsKey(u)) {
                dfs(u, c);
            }
        }
    }

    static void reverse(Integer []a) {
        Collections.reverse(Arrays.asList(a));
    }

    static boolean next(Integer []a) {
        int i = a.length - 1;
        while(a[i] == 0) i--;
        int c = 0;
        while(i >= 0 && a[i] == 1) {
            c++;
            i--;
        }
        if (i < 0) return false;
        a[i] = 1;
        for (int j = i + 1; j < a.length; j++) {
            a[j] = 0;
        }
        c--;
        for (int j = 0; j < c; j++) {
            a[a.length - 1 - j] = 1;
        }
        return true;
    }

    private static int bin(Integer []a, int l, int r, int x){
        if (l >= r) return l;
        int m = (l + r) / 2;
        if (a[m] > x) {
            return bin(a, l, m, x);
        }
        else if (a[m] < x || (m < a.length - 1 && a[m+1] == x)){
            return bin(a, m + 1, r, x);
        }
        return m + 1;
    }

    private static class SegmentTree {
        private long []d;
        private long []a;

        SegmentTree(int n) {
            a = new long[n];
            d = new long[5 * n];
        }

        void update(int v, int l, int r, int pos, long val) {
            if (l == r) {
                d[v] += val;
                a[l] += val;
            } else {
                int mid = (l + r) / 2;
                if (pos <= mid) {
                    update(v * 2, l, mid, pos, val);
                } else {
                    update(v * 2 + 1, mid + 1, r, pos, val);
                }
                d[v] = d[v * 2] + d[v * 2 + 1];
            }
        }

        int find(int v, int l, int r, long w) {
            if (v >= d.length) return -1;
            int mid = (l + r) / 2;
            if (d[v] <= w) return r;
            long o = w - d[v * 2];
            if (mid + 1 < a.length && o >= a[mid + 1]) {
                return find(v * 2 + 1, mid + 1, r, o);
            }
            if (w >= a[l])
                return find(v * 2, l, mid, w);
            return -1;
        }

        int iterFind(long w) {
            if (a[0] > w) return -1;
            int l = 0, r = a.length - 1;
            int v = 1;
            while (d[v] > w) {
                int mid = (l + r) / 2;
                long o = w - d[v * 2];
                if (mid + 1 < a.length && o >= a[mid + 1]) {
                    l = mid + 1;
                    v = v * 2 + 1;
                    w = o;
                } else {
                    v = v * 2;
                    r = mid;
                }
            }
            return r;
        }

        int get(int v, int vl, int vr, long w)
        {
            // cout << t[v] << "  "<< v << " " << vl << " " << vr<<" " << w << endl;
            if(d[v] < w) return -1;
            if(vl > vr) return -1;
            if(vl == vr)
            {
                if(d[v] > w) return vl - 1;
                else return -1;
            }
            if(d[v * 2] > w) return get(v * 2, vl, (vl + vr) / 2, w);
            else return get(v * 2 + 1, (vl + vr + 2) / 2, vr, w - d[v * 2]);
        }
    }

    private static class FenwickTree {
        long []t;

        FenwickTree(int n) {
            t = new long[n];
        }

        long sum (int r)
        {
            long result = 0;
            for (; r >= 0; r = (r & (r+1)) - 1)
                result += t[r];
            return result;
        }

        void inc (int i, long delta)
        {
            int n = t.length;
            for (; i < n; i = (i | (i+1)))
                t[i] += delta;
        }
    }

    public static void main(String[] args){
        FastScanner scanner = new FastScanner(System.in);
        PrintWriter printer = new PrintWriter(System.out);
        long M = (long)Math.pow(2, 32) - 1;
        //System.out.println(Integer.MAX_VALUE);
        int l = scanner.nextInt();
        Stack<Long>stack = new Stack<>();
        long x = 0;
        stack.add(1L);
        boolean flag = false;
        for (int i = 0; i < l; i++) {
            String cmd = scanner.next();
            if (cmd.equals("add")) {
                x += stack.peek();
                if (x > M) {
                    flag = true;
                    break;
                }
            }
            else if (cmd.equals("for")) {
                long p = scanner.nextLong();
                stack.add(Math.min(p * stack.peek(), 2 * M));
            }
            else {
                stack.pop();
            }
        }
        printer.println(flag ? "OVERFLOW!!!" : x);
        printer.flush();
        printer.close();
    }
}
/*
3 4
+ 1 3
? 3
+ 0 4
? 0

1 1
? 0

4 5
+ 0 4
+ 1 3
+ 2 1
+ 3 2
? 9

4 5
+ 0 4
+ 1 3
+ 2 1
+ 3 2
? 10

4 5
+ 0 4
+ 1 3
+ 2 1
+ 3 2
? 1000000

4 5
+ 0 0
+ 0 0
+ 0 0
+ 0 0
? 0
 */