#include<iostream> using namespace std; int main() { int n,d=0,e=1; cin>>n; int a[n+5],b[n+5]; for(int i=1;i<=n;i++) { cin>>a[i]>>b[i]; } for(int i=n;i>=1;i--) { a[i]=a[i]+b[i]; if(a[i]>=10) { a[i-1]=a[i-1]+a[i]/10; a[i]=a[i]%10; } d=d+a[i]*e; e=e*10; } cout<<d; return 0; }