#include<bits/stdc++.h> using namespace std; int main(){ int n,a[108],b[108],c[109],i,x=0; cin>>n; for(i=n;i>0;i--){ cin>>a[i]>>b[i]; } for(i=1;i<=n;i++){ c[i]=a[i]+b[i]+x; x=c[i]/10; c[i]=c[i]%10; } n-=x; for(i=n;i>0;i--){ cout<<c[i]; } }