#include "railroad.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll maxN = 17;
const ll maxM = (1 << 16) + 5;
const ll INF = 1e18;
ll n;
vector<ll> S, T;
ll memo[maxM][maxN];
ll dp(ll mask, ll cur) {
if (__builtin_popcountll(mask) == 1) {return 0;}
else if (memo[mask][cur] != -1) {return memo[mask][cur];}
ll ret = INF;
ll prv = mask ^ (1ll << cur);
for (ll b = 0; b < n; b++) {
if (prv & (1ll << b)) {
ret = min(ret, dp(prv, b) + max(0ll, T[b] - S[cur]));
}
}
//printf("memo[%lld][%lld] = %lld\n", mask, cur, ret);
return memo[mask][cur] = ret;
}
ll plan_roller_coaster(vector<int> s, vector<int> t) {
n = s.size();
ll maxMask = (1 << n) - 1;
for (auto i : s) {S.push_back(i);}
for (auto i : t) {T.push_back(i);}
for (ll i = 0; i < n; i++) {
for (ll mask = 0; mask <= maxMask; mask++) {
memo[mask][i] = -1;
}
}
ll ans = INF;
for (ll i = 0; i < n; i++) {
ans = min(ans, dp(maxMask, i));
}
return ans;
}
#ifdef Zanite
int main() {
int n;
assert(1 == scanf("%d", &n));
std::vector<int> s(n), t(n);
for (int i = 0; i < n; ++i)
assert(2 == scanf("%d%d", &s[i], &t[i]));
long long ans = plan_roller_coaster(s, t);
printf("%lld\n", ans);
return 0;
}
#endif
