#include <iostream> #include <vector> #include <algorithm> using namespace std; bool is_kadomatsu(int a, int b, int c){ if(a==b || b==c || c==a) return false; if(a<b && b>c) return true; if(a>b && b<c) return true; return false; } int main(){ int n = 7; vector<int> a(n); for(int i=0; i<n; i++) cin >> a[i]; sort(a.begin(), a.end()); do{ bool ok = true; for(int i=2; i<n; i++){ if( (is_kadomatsu(a[i-2], a[i-1], a[i]) && a[i-2] < a[i]) == false){ ok = false; } } if(ok){ cout << "YES" << endl; return 0; } }while(next_permutation(a.begin(), a.end())); cout << "NO" << endl; return 0; }