#include <iostream> #include <cstdio> using namespace std; int a[109]; int b[109]; int main() { int n; cin>>n; for(int i=1;i<=n;i++){ scanf("%d",&a[i]); scanf("%d",&b[i]); a[i]+=b[i]; } for(int i=n;i>=0;i--){ if(a[i]>=10){ a[i-1] += a[i]/10; a[i]=a[i]%10;; } } if(a[0]!=0){ for(int i=0;i<=n;i++){ printf("%d",a[i]); } }else{ for(int i=1;i<=n;i++){ printf("%d",a[i]); } } return 0; }