def solve():
    n, q = map(int, input().split())  # Number of snakes and events
    events = [input().strip() for _ in range(q)]  # List of events
 
    # Initialize the snake positions: all snakes start in their own cell, so (1, 1) for each snake.
    snakes = [(1, 1)] * n  # List of tuples representing the (left, right) positions of each snake.
 
    # Set to track occupied cells to avoid collisions
    occupied = set(range(1, n + 1))  # Initially, each snake occupies one cell from 1 to n
 
    # To keep track of the maximum occupied cell after each step
    max_occupied = n  # Initially, the maximum occupied cell is n (since the snakes occupy 1 to n).
 
    # Process each event
    for event in events:
        snake_idx = int(event[0]) - 1  # Snake index is 1-based, so we adjust to 0-based.
        if event[2] == '+':  # Grow the snake
            # Current position of the snake
            left, right = snakes[snake_idx]
            # Try to grow the snake
            new_right = right + 1
            if new_right not in occupied:
                # Update snake's position and mark new cell as occupied
                snakes[snake_idx] = (left, new_right)
                occupied.add(new_right)
                # Update max_occupied
                max_occupied = max(max_occupied, new_right)
        elif event[2] == '-':  # Shrink the snake
            # Current position of the snake
            left, right = snakes[snake_idx]
            # Try to shrink the snake
            new_left = left + 1
            # Update snake's position
            snakes[snake_idx] = (new_left, right)
            # Mark the cell we just freed as unoccupied
            occupied.remove(left)
 
    # Output the minimum possible score (maximum occupied cell after all events)
    print(max_occupied)
 

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5 13
5 +
3 +
5 -
2 +
4 +
3 +
5 +
5 -
2 +
3 -
3 +
3 -
2 +