{"raw_statement":[{"iden":"problem statement","content":"Determine whether there is a way to line up $N$ people, numbered $1$ to $N$, in a row side by side to satisfy all of the $M$ conditions in the following format.\n\n*   Condition: Person $A_i$ and Person $B_i$ are adjacent."},{"iden":"constraints","content":"*   $2 \\leq N \\leq 10^5$\n*   $0 \\leq M \\leq 10^5$\n*   $1\\leq A_i < B_i \\leq N$\n*   All pairs $(A_i,B_i)$ are distinct."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$ $M$\n$A_1$ $B_1$\n$\\vdots$\n$A_M$ $B_M$"},{"iden":"sample input 1","content":"4 2\n1 3\n2 3"},{"iden":"sample output 1","content":"Yes\n\nOne way to satisfy all the conditions is to line them up in the order $4,1,3,2$."},{"iden":"sample input 2","content":"4 3\n1 4\n2 4\n3 4"},{"iden":"sample output 2","content":"No\n\nThere is no way to line them up to satisfy all the conditions."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}