#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define ent "\n"
const int inf = (int)1e9 + 100;
const int maxn = 5e5 + 100;
const ll INF = (ll)1e18;
const int MOD = 1e9 + 7;
const int maxl = 62500;
const ll P = 31, T = 0;
int n;
int a[maxn];
int b[maxn];
void test(){
cin >> n;
vector<int> v;
for(int i = 1; i <= n; i++){
cin >> a[i] >> b[i];
if(a[i] > b[i]){
v.push_back(i);
}
}
ll ans = 0;
for(int i = n; i > 0; i--){
if(a[i] > b[i]) continue;
while(a[i] < b[i]){
int cnt = min(b[i] - a[i], a[v.back()] - b[v.back()]);
a[i] += cnt; a[v.back()] -= cnt;
ans += 1ll * cnt * abs(v.back() - i);
if(a[v.back()] == b[v.back()]) v.pop_back();
}
}
cout << ans;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
// #ifndef ONLINE_JUDGE
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
// #endif
int t = 1;
if(T) cin >> t;
while(t--) test();
}
