#include<iostream> #include<algorithm> using namespace std; int n,a[1005],b[1005]; bool cmp(int a,int b){ return a<b; } int main(){ int sum=0; int k; cin>>n; for(int i=1;i<=n;i++){ cin>>a[i]>>b[i]; sum+=a[i]; sort(b,b+1,cmp); k=sum*b[1]; } cout<<k; return 0; }