import json

data = [
    {"category": "A", "value": 1},
    {"category": "A", "value": 2},
    {"category": "B", "value": 3},
    {"category": "B", "value": 4}
]

first_values = {}

for item in data:
    category = item["category"]
    value = item["value"]
    if category not in first_values:
        first_values[category] = value

for category, value in first_values.items():
    print(f"Category: {category}, First Value: {value}")