#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define all(a) a.begin(),a.end()
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef unsigned long long ull;
typedef vector<int> vi;
void solve(){
int n; cin >> n;
vector<ll> pref(n+1,0);
priority_queue<ll> pq;
ll ans = 0;
for(int i = 1; i <= n; i++){
int a,b; cin >> a >> b;
pref[i] = a-b + pref[i-1];
}
vector<vector<int>> dp(n+1,vector<int>(pref[n]+1,1e9));
dp[0][0] = 0;
for(int i = 1; i <= n; i++){
int mn = 1e9;
for(int j = 0; j <= pref[n]; j++){
mn = min(mn,dp[i-1][j]);
dp[i][j] = mn + abs(j-pref[i]);
}
}
cout << dp[n][pref[n]];
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
int t = 1;
// cin >> t;
while(t--){solve();}
}
