{"raw_statement":[{"iden":"problem statement","content":"There are $N$ people. The family name and given name of the $i$\\-th person $(1 \\leq i \\leq N)$ are $S_i$ and $T_i$, respectively.\nDetermine whether there is a pair of people with the same family and given names. In other words, determine whether there is a pair of integers $(i,j)$ such that $1 \\leq i \\lt j \\leq N$, $S_i=S_j$, and $T_i=T_j$."},{"iden":"constraints","content":"*   $2 \\leq N \\leq 1000$\n*   $N$ is an integer.\n*   Each of $S_i$ and $T_i$ is a string of length between $1$ and $10$ (inclusive) consisting of English lowercase letters."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$S_1$ $T_1$\n$S_2$ $T_2$\n$\\hspace{0.6cm}\\vdots$\n$S_N$ $T_N$"},{"iden":"sample input 1","content":"3\ntanaka taro\nsato hanako\ntanaka taro"},{"iden":"sample output 1","content":"Yes\n\nThe first and third persons have the same family and given names."},{"iden":"sample input 2","content":"3\nsaito ichiro\nsaito jiro\nsaito saburo"},{"iden":"sample output 2","content":"No\n\nNo two persons have the same family and given names."},{"iden":"sample input 3","content":"4\nsypdgidop bkseq\nbajsqz hh\nozjekw mcybmtt\nqfeysvw dbo"},{"iden":"sample output 3","content":"No"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}