#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
#define ll long long
ll mod = 998244353;
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ll binpow(ll a, ll b)
{
ll res = 1;
while (b>0)
{
if (b&1)
res = (res*a)%mod;
a = (a*a)%mod;
b>>=1;
}
return res;
}
ll gcd(ll x, ll y)
{
if (y==0)
return x;
return gcd(y, x%y);
}
void solve()
{
ll n;
cin>>n;
vector<ll>v(n+1, 0);
for (int i=1 ; i<=n ; i++)
{
ll x,y;
cin>>x>>y;
v[i] = y-x;
}
ll id = 0;
ll res = 0;
for (int i=1 ; i<=n ;i++)
{
while (v[i]>0)
{
while (v[id]>=0) id++;
if (v[i]>abs(v[id]))
{
v[i] += v[id];
res += abs(i-id)*abs(v[id]);
v[id] = 0;
}
else
{
v[id] += v[i];
res += abs(i-id)*v[i];
v[i] = 0;
break;
}
}
}
cout<<res<<endl;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
ll tt = 1;
// cin>>tt;
while (tt--)
{
solve();
}
return 0;
}
