#include <bits/stdc++.h>      //gua le aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
using namespace std;

int n,ta[2010],tb[2010];

int dfs(int x,int l,int a,int b){
    if (x>n) return max(a,b);
    if (!l){
        return min(dfs(2,1,ta[1],0),dfs(2,2,0,tb[1]));
    }
    if (l==1){
        return min(dfs(x+1,1,a+ta[x],b),dfs(x+1,2,a,max(b,a-ta[x-1])+tb[x]));
    }
    if (l==2){
        return min(dfs(x+1,1,max(a,b-tb[x-1])+ta[x],b),dfs(x+1,2,b+tb[x],b));
    }
}

int main(){
    freopen("task.in","r",stdin);
    freopen("task.out","w",stdout);
    
    scanf("%d",&n);
    for (int i=1;i<=n;i++) scanf("%d %d",&ta[i],&tb[i]);
    int res=dfs(1,0,0,0);
    printf("%d",res);
    
    return 0;
}