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