#include <iostream> #include <cstring> #include <cmath> using namespace std; int n,a[200],b[200],c[200]; int main() { cin>>n; for (int i=n;i>=1;--i) cin>>a[i]>>b[i]; // int x=0; for (int i=1;i<=n;++i) { c[i]=a[i]+b[i]+x; if (c[i]>9) { c[i]-=10; x=1; } else x=0; } if (c[n+1]) ++n; for (int i=n;i>=1;--i) printf("%d",c[i]); return 0; }