/* //Works 001 (鸡兔同笼) #include<iostream> #include<cstdio> #include<cstring> #include<cmath> using namespace std; int main(){ int n=0,x=0,s=0; for(int i=1;n<=35;i++){ x=35-i; if(i*2+x*4==94){ cout<<"有"<<x<<"只兔子,有"<<i<<"只鸡."; return 0; } } return 0; } //Works 007 (换算纸币) #include<iostream> #include<cstdio> #include<cstring> #include<cmath> using namespace std; int main(){ int n=0,x=0,s=0; for(int i=0;i*50<=300;i++){ for(int j=0;j*20<=300;j++){ for(int k=0;k*10<=300;k++){ if(i*50+j*20+k*10==300){ cout<<i<<" "<<j<<" "<<k<<endl; } } } } return 0; }*/ //1456 大力水手吃蔬菜 #include<iostream> #include<cstdio> #include<cstring> #include<cmath> using namespace std; int main(){ int n,a=0,b=0,s=0,m=101; cin>>n; for(int i=1;i<=n;i++){ cin>>a>>b; if(b<m){ m=b; } s+=m*a; } cout<<s; return 0; }