#include<iostream> using namespace std; int arra[101]; //数量 int arrb[101]; //价格 int main(){ int n,money=0,minn=200; cin>>n; for(int i=0;i<n;i++){ cin>>arra[i]>>arrb[i]; if(minn>arrb[i]) minn=arrb[i]; money+=arra[i]*minn; } cout<<money; return 0; }