std::unordered_map<std::string, std::string> inACopy;
    std::unordered_map<std::string, std::string> inBCopy;
    std::vector<std::string> CommonAncestorPrefixes;

    std::unordered_map<std::string, std::string> manAMap;
    std::unordered_map<std::string, std::string> manBMap;

    for(auto x: manifestA) {
        std::string prefix = withoutChecksum(x);
        manAMap[prefix] = x;
    }

    for(auto x: manifestB) {
        std::string prefix = withoutChecksum(x);
        manBMap[prefix] = x;
    }


    for(auto x: manifestA) {
        std::string prefix = withoutChecksum(x);
        if (manBMap.count(prefix)) {
            // If they're the same
            if (manBMap[prefix] == x) {
                // Do nothing, checksums match
                // Left in for clarity
            }
            else {
                // File is same, but dif checksum.
                CommonAncestorPrefixes.push_back(prefix);
                inACopy[prefix] = x;
                inBCopy[prefix] = manBMap[prefix];

            }
        }
        else {
            // Copy x
            // The entire file is only in A
        }
    }