#include <iostream> using namespace std; int n,numa[5003],numb[5003],ansc[5001]; int main() { scanf("%d",&n); for (int i=n;i>=1;--i) scanf("%d%d",numa+i,numb+i); // for (int i=n;i>=1;--i) { ansc[i]+=(numa[i]+numb[i]); ansc[i+1]+=ansc[i]/10; ansc[i]%=10; } if (ansc[n+1]) ++n; // for (int i=n;i>=1;--i) printf("%d",ansc[i]); return 0; }