#include using namespace std; #define int long long #define rep(i,n) for(int (i)=0;(i)<(n);(i)++) #define rrep(i,n) for(int (i)=((n)-1);(i)>=0;(i)--) #define itn int #define all(x) (x).begin(),(x).end() #define F first #define S second const long long INF = 1LL << 60; const int MOD = 1000000007; template inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } signed main(void){ int n; cin>>n; vector a(n-1); vector b(n-1); int sum = 0; rep(i,n-1){ cin>>a[i]>>b[i]; sum += b[i]; } cout<