#include <bits/stdc++.h> using namespace std; int b[5001]; int a[5001]; int c[6000]; int main() { int n; cin >> n; int x = 0; //memset(c,0,sizeof(c)); for (int i = 1; i <= n; i++) { cin >> a[i] >> b[i]; } for (int i = n; i >= 1; i--) { c[i] = a[i] + b[i] + x; x = c[i] / 10; if(c[i] >= 10) { c[i] %= 10; //c[i - 1] += 1; } } for (int i = 1; i <= n; i++) { cout << c[i]; } }