import java.util.*;
import java.io.*;

class Day8 {
    private static void updateRegister(HashMap<String, Integer> register, String[] instruction) {
        if ("inc" == instruction[1]) {
            register.put(instruction[0], register.get(instruction[0]) + Integer.parseInt(instruction[2]));
        } else {
            register.put(instruction[0], register.get(instruction[0]) - Integer.parseInt(instruction[2]));
        }
    }

    public static void main(String[] args) throws FileNotFoundException {
        Scanner sc = new Scanner(new File("Day8_input"));
        HashMap<String, Integer> register = new HashMap<String, Integer>();
        String[] instruction = new String[7];
        while (sc.hasNext()) {
            instruction = sc.nextLine().split(" ");
            // System.out.println(Arrays.toString(instruction));
            if (!register.keySet().contains(instruction[0])) {
                register.put(instruction[0], 0);
            }
            if (!register.keySet().contains(instruction[4])) {
                register.put(instruction[4], 0);
            }
            switch (instruction[5]) {
                case "<":
                    if (register.get(instruction[4]) < Integer.parseInt(instruction[6])) {
                        updateRegister(register, instruction);
                    }
                    //System.out.println("<");
                    break;
                case ">":
                    if (register.get(instruction[4]) > Integer.parseInt(instruction[6])) {
                        updateRegister(register, instruction);
                    }
                    //System.out.println(">");
                    break;
                case "==":
                    if (register.get(instruction[4]) == Integer.parseInt(instruction[6])) {
                        updateRegister(register, instruction);
                    }
                    break;
                case ">=":
                    if (register.get(instruction[4]) >= Integer.parseInt(instruction[6])) {
                        updateRegister(register, instruction);
                    }
                    // System.out.println(">=");
                    break;
                case "<=":
                    if (register.get(instruction[4]) <= Integer.parseInt(instruction[6])) {
                        updateRegister(register, instruction);
                    }
                    break;
                default:
                    if (register.get(instruction[4]) != Integer.parseInt(instruction[6])) {
                        updateRegister(register, instruction);
                    }
                    break;
            }
        }
        System.out.println(Collections.max(register.values()));
    }
}