#include<iostream> #include<cstdio> #include<cstring> #include<string> #include<vector> #include<cmath> #include<algorithm> #include<map> #include<queue> #include<deque> using namespace std; typedef long long int LL; typedef pair<int,int> P; typedef pair<int,pair<int,int> > PP; typedef pair<LL,int> LP; vector<P> v1; LL dp[2005][1005]; int main(){ int n; int i,j,k; LL a,b,c; cin>>n; for(i=0;i<n;i++){ cin>>a>>b; v1.push_back(make_pair(b,a)); } sort(v1.rbegin(),v1.rend()); memset(dp,-1,sizeof(dp)); dp[0][0]=0; for(i=0;i<n;i++){ b=v1[i].first,a=v1[i].second; for(j=0;j<=n/3;j++){ if(dp[i][j]==-1)continue; dp[i+1][j+1]=dp[i][j]; c=dp[i][j]+a+b*(i-j); if(dp[i+1][j]==-1 || dp[i+1][j]>c)dp[i+1][j]=c; } } a=dp[n][0]; for(i=0;i<=n/3;i++){ if(a>dp[n][i])a=dp[n][i]; } cout<<a<<endl; return 0; }