class Solution {
public:
    int leastBricks(vector<vector<int>>& wall) {
        unordered_map<int, int> sum_count_map;
        int maxSum = 0;

        for(auto row_v:wall){
            int sum = 0;
            //Skipping last elem
            for(int idx=0; idx<row_v.size()-1; idx++){
                sum += row_v[idx];
                sum_count_map[sum]++;
            }
        }

        for(auto kv:sum_count_map){
            if(kv.second>maxSum)
                maxSum = kv.second;
        }

        return wall.size()-maxSum;
    }
};