#include<bits/stdc++.h>

using namespace std;

const int INF=10000000;

int a[10000],b[10000];

int dp[1000+10][10000];

const int pianyi=5000;

int main(){

int n;

cin>>n;

int sum=0;

for(int i=1;i<=n;i++)scanf("%d%d",&a[i],&b[i]),sum+=a[i]+b[i];

   for (int i = 1; i <= n; i ++)

        for (int j = 0; j <= 6*n; j ++) dp[i][j] = INF;

   dp[1][a[1]]=0;dp[1][b[1]]=1;

   for(int i=2;i<=n;i++){

       for(int j=0;j<=6*n;j++){

           if(j>=a[i])dp[i][j]=min(dp[i][j],dp[i-1][j-a[i]]);

           if(j>=b[i])dp[i][j]=min(dp[i][j],dp[i-1][j-b[i]]+1);

       }

   }

   int temp1=INF,ans=INF;

   for(int i=0;i<=sum;i++){

       if(dp[n][i]!=INF){

              if(abs(2*i-sum)<temp1){

                  ans=dp[n][i];

                  temp1=abs(2*i-sum);

              }

             else if(abs(i-(sum-i)) == temp1)ans=min(ans,dp[n][i]);

       }

   }

   cout<<ans<<endl;

    return 0;

}