#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <utility>

int main() {
    const int BIG_CONST = 2000000000;
    size_t count_coins;
    std::cin >> count_coins;
    std::vector<int> coins(count_coins);
    std::vector<int> lifetime(count_coins);
    for (size_t i = 0; i < count_coins; ++i) {
            std::cin >> coins[i];
            std::cin >> lifetime[i];
    }
    std::vector<std::vector<std::pair<int, int>>> ans(count_coins,
            std::vector<std::pair<int, int>> (count_coins));
    size_t count = 0;
    while (count < count_coins) {
        for (size_t ii = 0; ii < count_coins; ++ii) {
            size_t jj = ii + count;
            if (jj < count_coins) {
                if (ii == jj) {
                    ans[ii][jj].first = 0;
                    ans[ii][jj].second = 0;
                } else {
                    ans[ii][jj].first = std::min(ans[ii + 1][jj].first +
                            abs(coins[ii] - coins[ii + 1]),
                            ans[ii + 1][jj].second + abs(coins[ii] - coins[jj]));
                    ans[ii][jj].second = std::min(ans[ii][jj - 1].first +
                            abs(coins[ii] - coins[jj]),
                            ans[ii][jj - 1].second + abs(coins[jj - 1] - coins[jj]));
                    if (ans[ii][jj].first > lifetime[ii]) {
                        ans[ii][jj].first = BIG_CONST;
                    }
                    if (ans[ii][jj].second > lifetime[jj]) {
                        ans[ii][jj].second = BIG_CONST;
                    }
                }
            }
        }
        ++count;
    }

    int result;
    result = std::min(ans[0][count_coins-1].first, ans[0][count_coins-1].second);
    if (result < BIG_CONST) {
        std::cout << result;
    } else {
        std::cout << "No solution";
    }
    return 0;
}