#include<bits/stdc++.h> using namespace std; int n,a1[101],b1[101],a,b,b2,jia; int main() { cin>>n; for(int i=1;i<=n;i++){ cin>>a>>b; a1[i]=a;//吃 b1[i]=b;//价格 } b2=2000; for(int i=1;i<=n;i++){ for(int j=1;j<=n;j++){ if(b1[i]<b2){ b2=b1[i]; } continue; } jia+=a1[i]*b2; } cout<<jia; return 0; }