#include using namespace std; int main(void){ int n; cin>>n; int A[105]; for(int i=0; i>A[i]; } int target = A[0] + A[n - 1]; for(int i = 0; i < n; i++){ if(A[i] + A[n-1-i] != target){ cout << "No"; return 0; } } cout<<"Yes"; return 0; }