#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define db double
#define pii pair<int,int>
#define mp make_pair
#define fi first
#define se second
const int N = 2010;
const ll inf = 1e17;
 
 
ll read(){
    ll x = 0,f = 1;char c = getchar();
    for(;c < '0' || c > '9';c = getchar())if(c == '-')f = -1;
    for(;c >= '0' && c <= '9';c = getchar())x = (x<<1) + (x<<3) + c-'0';
    return x * f;
}
 
int n,ans = INT_MAX;
pii f[N][2];
int a[N],b[N];
 
 
int main(){
    freopen("task.in","r",stdin);
    freopen("task.out","w",stdout);
    n = read();
    for(int i = 1;i <= n;i++)a[i] = a[i-1] + read(),b[i] = b[i-1] + read();
    memset(f,0x3f,sizeof f);
    f[0][0] = f[0][1] = mp(0,0);
    for(int i = 1;i <= n;i++){
        for(int j = 0;j < i;j++){
            if(max(max(f[j][1].se - (b[j] - b[j-1]),f[j][1].fi) + (a[i] - a[j]),f[j][1].se) < max(f[i][0].fi,f[i][0].se))
                f[i][0] = mp(max(f[j][1].se - (b[j] - b[j-1]),f[j][1].fi) + (a[i] - a[j]),f[j][1].se);
            if(max(f[j][0].fi,max(f[j][0].fi - (a[j] - a[j-1]),f[j][0].se) + (b[i] - b[j])) < max(f[i][1].fi,f[i][1].se))
                f[i][1] = mp(f[j][0].fi,max(f[j][0].fi - (a[j] - a[j-1]),f[j][0].se) + (b[i] - b[j]));
        }
    }
    printf("%d\n",min(max(f[n][1].fi,f[n][1].se),max(f[n][0].fi,f[n][0].se)));
    
    
    return 0;
    
}