#include <iostream>
#include <vector>

int main() {

    int segnum;
    std::cin >> segnum;

    std::vector<int> A;
    std::vector<int> B;
    std::vector<int> C;
    std::vector<int> D;
    std::vector<int> E;


    for(int i = 0; i < segnum; i++) {
        int curr;
        std::cin >> curr;
        A.push_back(curr);

        std::cin >> curr;
        B.push_back(curr);

        std::cin >> curr;
        C.push_back(curr);

        std::cin >> curr;
        D.push_back(curr);

        std::cin >> curr;
        E.push_back(curr);
    }

    int currUp, currDown, currMid;

    currMid = A[0] + D[0];

    for(int i = 0; i < segnum; ++i) {
        currUp = std::min(A[i], std::min(B[i], currMid));
        currMid -= currUp;
        currDown = std::min(D[i], std::min(E[i], currMid));
        currMid -= currDown;
                                                                   // '=' aby se to nekam poslalo
        if( std::min( A[i]-currUp, std::min(C[i], E[i]-currDown )) >= std::min( D[i]-currDown, std::min(C[i], B[i]-currUp )) ) {
            currUp += std::min(currMid, std::min( A[i]-currUp, std::min(C[i], E[i]-currDown )));
        } else {
            currDown += std::min(currMid, std::min( D[i]-currDown, std::min(C[i], B[i]-currUp )));
        }

        currMid = currUp + currDown;
    }

    std::cout << currMid << std::flush;

    return 0;
}