#include using namespace std; typedef signed long long ll; #undef _P #define _P(...) (void)printf(__VA_ARGS__) #define FOR(x,to) for(x=0;x<(to);x++) #define FORR(x,arr) for(auto& x:arr) #define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) //------------------------------------------------------- int N,M; int A[1010]; vector E[1010]; void solve() { int i,j,k,l,r,x,y; string s; cin>>N>>M; FOR(i,N) cin>>A[i]; FOR(i,M) { cin>>x>>y; E[x-1].push_back(y-1); E[y-1].push_back(x-1); } FOR(i,N) { set C[2]; FORR(e,E[i]) { if(A[e]A[i]) C[1].insert(A[e]); } if(C[0].size()>=2) return _P("YES\n"); if(C[1].size()>=2) return _P("YES\n"); } _P("NO\n"); } int main(int argc,char** argv){ string s;int i; if(argc==1) ios::sync_with_stdio(false), cin.tie(0); FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin); cout.tie(0); solve(); return 0; }